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help / color / mirror / Atom feedFrom: Bruce Momjian <[email protected]>
To: David Fetter <[email protected]>
Cc: PostgreSQL Docs <[email protected]>
Cc: PostgreSQL Patches <[email protected]>
Subject: Re: [PATCHES] Example for UPDATE FROM with correllation
Date: Thu, 19 Jan 2006 18:10:17 -0500 (EST)
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
Patch applied, with minor space adjustments to HEAD and 8.1.X. I also
noticed a few earlier examples were missing paragraph formatting.
---------------------------------------------------------------------------
David Fetter wrote:
> Folks,
>
> Please find enclosed a doc patch that adds an example of a correllated
> UPDATE.
>
> Cheers,
> D
> --
> David Fetter [email protected] http://fetter.org/
> phone: +1 415 235 3778
>
> Remember to vote!
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>
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--
Bruce Momjian | http://candle.pha.pa.us
[email protected] | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
Index: doc/src/sgml/ref/update.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/ref/update.sgml,v
retrieving revision 1.33
diff -c -c -r1.33 update.sgml
*** doc/src/sgml/ref/update.sgml 12 Oct 2005 23:19:22 -0000 1.33
--- doc/src/sgml/ref/update.sgml 19 Jan 2006 23:08:08 -0000
***************
*** 205,218 ****
--- 205,236 ----
WHERE accounts.name = 'Acme Corporation'
AND employees.id = accounts.sales_person;
</programlisting>
+ </para>
+ <para>
Perform the same operation, using a sub-select in the
<literal>WHERE</literal> clause:
<programlisting>
UPDATE employees SET sales_count = sales_count + 1 WHERE id =
(SELECT sales_person FROM accounts WHERE name = 'Acme Corporation');
</programlisting>
+ </para>
+ <para>
+ Now that all the papers are signed, update the most recently closed
+ deal of the travelling salesperson who closed the Rocket Powered
+ Skates deal with the Acme Corporation.
+ <programlisting>
+ UPDATE employees SET last_closed_deal = deal.id
+ FROM accounts JOIN deals ON (account.id = deal.account_id)
+ WHERE deal.employee_id = employees.id
+ AND deal.name = 'Rocket Powered Skates'
+ AND accounts.name = 'Acme Corporation'
+ ORDER BY deal.signed_date DESC LIMIT 1;
+ </programlisting>
+ </para>
+
+ <para>
Attempt to insert a new stock item along with the quantity of stock. If
the item already exists, instead update the stock count of the existing
item. To do this without failing the entire transaction, use savepoints.
Attachments:
[text/plain] /bjm/diff (1.6K, 2-%2Fbjm%2Fdiff)
download | inline:
Index: doc/src/sgml/ref/update.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/ref/update.sgml,v
retrieving revision 1.33
diff -c -c -r1.33 update.sgml
*** doc/src/sgml/ref/update.sgml 12 Oct 2005 23:19:22 -0000 1.33
--- doc/src/sgml/ref/update.sgml 19 Jan 2006 23:08:08 -0000
***************
*** 205,218 ****
--- 205,236 ----
WHERE accounts.name = 'Acme Corporation'
AND employees.id = accounts.sales_person;
</programlisting>
+ </para>
+ <para>
Perform the same operation, using a sub-select in the
<literal>WHERE</literal> clause:
<programlisting>
UPDATE employees SET sales_count = sales_count + 1 WHERE id =
(SELECT sales_person FROM accounts WHERE name = 'Acme Corporation');
</programlisting>
+ </para>
+ <para>
+ Now that all the papers are signed, update the most recently closed
+ deal of the travelling salesperson who closed the Rocket Powered
+ Skates deal with the Acme Corporation.
+ <programlisting>
+ UPDATE employees SET last_closed_deal = deal.id
+ FROM accounts JOIN deals ON (account.id = deal.account_id)
+ WHERE deal.employee_id = employees.id
+ AND deal.name = 'Rocket Powered Skates'
+ AND accounts.name = 'Acme Corporation'
+ ORDER BY deal.signed_date DESC LIMIT 1;
+ </programlisting>
+ </para>
+
+ <para>
Attempt to insert a new stock item along with the quantity of stock. If
the item already exists, instead update the stock count of the existing
item. To do this without failing the entire transaction, use savepoints.
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