8000 Document effect of constant folding on CASE. · postgres/postgres@d53f7cf · GitHub
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Document effect of constant folding on CASE.
Back-patch to all supported versions. Laurenz Albe
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‎doc/src/sgml/func.sgml

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@@ -10563,6 +10563,16 @@ SELECT a,
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SELECT ... WHERE CASE WHEN x <> 0 THEN y/x > 1.5 ELSE false END;
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</programlisting>
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</para>
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<note>
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<para>
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As described in <xref linkend="xfunc-volatility">, functions and
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operators marked <literal>IMMUTABLE</literal> can be evaluated when
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the query is planned rather than when it is executed. This means
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that constant parts of a subexpression that is not evaluated during
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query execution might still be evaluated during query planning.
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</para>
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</note>
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</sect2>
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<sect2 id="functions-coalesce-nvl-ifnull">

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