database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-20 05:03:10 +03:00
Code Activity

Document effect of constant folding on CASE.

Browse Source 
Back-patch to all supported versions.

Laurenz Albe
This commit is contained in:
Noah Misch
2013-06-26 19:51:56 -04:00
parent f44eedc3f0
commit ca1700130b
1 changed files with 10 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
doc/src/sgml/func.sgml
View File

@ -9290,6 +9290,16 @@ SELECT a,
SELECT ... WHERE CASE WHEN x <> 0 THEN y/x > 1.5 ELSE false END; SELECT ... WHERE CASE WHEN x <> 0 THEN y/x > 1.5 ELSE false END;
</programlisting> </programlisting>
</para> </para>
<note>
<para>
As described in <xref linkend="xfunc-volatility">, functions and
operators marked <literal>IMMUTABLE</literal> can be evaluated when
the query is planned rather than when it is executed. This means
that constant parts of a subexpression that is not evaluated during
query execution might still be evaluated during query planning.
</para>
</note>
</sect2> </sect2>
<sect2> <sect2>