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help / color / mirror / Atom feedFrom: Bruce Momjian <[email protected]>
To: Eugen Konkov <[email protected]>
Cc: Tom Lane <[email protected]>
Cc: [email protected]
Subject: Re: Why 'infinity' is not in range '[2019-01-02, infinity]'?
Date: Wed, 6 Nov 2019 08:33:28 -0500
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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On Wed, Nov 6, 2019 at 12:15:17PM +0200, Eugen Konkov wrote:
> ! Specifying a missing bound as exclusive is automatically converted
> ! to inclusive, e.g., <literal>[,]</literal> is automatically converted
> ! to <literal>(,)</literal>
>
> Misspell?
>
> You say:
> exclusive is automatically converted to inclusive
> But then:
> [,] is automatically converted to (,)
>
> which one is correct?
My mistake. Thanks for finding that. Updated patch attached, plus I
improved the second paragraph.
--
Bruce Momjian <[email protected]> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ As you are, so once was I. As I am, so you will be. +
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Attachments:
[text/x-diff] range.diff (3.0K, 2-range.diff)
download | inline diff:
diff --git a/doc/src/sgml/rangetypes.sgml b/doc/src/sgml/rangetypes.sgml
new file mode 100644
index 3a034d9..b75fb3a
*** a/doc/src/sgml/rangetypes.sgml
--- b/doc/src/sgml/rangetypes.sgml
*************** SELECT isempty(numrange(1, 5));
*** 131,159 ****
<title>Infinite (Unbounded) Ranges</title>
<para>
! The lower bound of a range can be omitted, meaning that all points less
! than the upper bound are included in the range. Likewise, if the upper
! bound of the range is omitted, then all points greater than the lower bound
! are included in the range. If both lower and upper bounds are omitted, all
! values of the element type are considered to be in the range.
! </para>
!
! <para>
! This is equivalent to considering that the lower bound is <quote>minus
! infinity</quote>, or the upper bound is <quote>plus infinity</quote>,
! respectively. But note that these infinite values are never values of
! the range's element type, and can never be part of the range. (So there
! is no such thing as an inclusive infinite bound — if you try to
! write one, it will automatically be converted to an exclusive bound.)
</para>
<para>
! Also, some element types have a notion of <quote>infinity</quote>, but that
! is just another value so far as the range type mechanisms are concerned.
! For example, in timestamp ranges, <literal>[today,]</literal> means the same
! thing as <literal>[today,)</literal>. But <literal>[today,infinity]</literal> means
! something different from <literal>[today,infinity)</literal> — the latter
! excludes the special <type>timestamp</type> value <literal>infinity</literal>.
</para>
<para>
--- 131,156 ----
<title>Infinite (Unbounded) Ranges</title>
<para>
! The lower bound of a range can be omitted, meaning that all
! values less than the upper bound are included in the range, e.g.,
! <literal>(,3]</literal>. Likewise, if the upper bound of the range
! is omitted, then all values greater than the lower bound are included
! in the range. If both lower and upper bounds are omitted, all values
! of the element type are considered to be in the range. Specifying a
! missing bound as inclusive is automatically converted to exclusive,
! e.g., <literal>[,]</literal> is converted to <literal>(,)</literal>.
! You can think of these missing values as +/-infinity, but they are
! special range type values and are considered to be beyond any range
! element type's +/-infinity values.
</para>
<para>
! Element types that have the notion of <quote>infinity</quote> can
! use them as explicit bound values. For example, with timestamp
! ranges, <literal>[today,infinity)</literal> excludes the special
! <type>timestamp</type> value <literal>infinity</literal>,
! while <literal>[today,infinity]</literal> include it, as does
! <literal>[today,)</literal> and <literal>[today,]</literal>.
</para>
<para>
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