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Add documentation mention that 7 != NULL also returns NULL.

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Bruce Momjian 2011-12-01 09:17:51 -05:00
parent bc9306f4c5
commit ebbcba75b4
1 changed files with 2 additions and 2 deletions
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4
doc/src/sgml/func.sgml
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@ -364,8 +364,8 @@
</indexterm> </indexterm>
Ordinary comparison operators yield null (signifying <quote>unknown</>), Ordinary comparison operators yield null (signifying <quote>unknown</>),
not true or false, when either input is null. For example, not true or false, when either input is null. For example,
<literal>7 = NULL</> yields null. When this behavior is not suitable, <literal>7 = NULL</> yields null, as does <literal>7 &lt;&gt; NULL</>. When
use the this behavior is not suitable, use the
<literal>IS <optional> NOT </> DISTINCT FROM</literal> constructs: <literal>IS <optional> NOT </> DISTINCT FROM</literal> constructs:
<synopsis> <synopsis>
<replaceable>expression</replaceable> IS DISTINCT FROM <replaceable>expression</replaceable> <replaceable>expression</replaceable> IS DISTINCT FROM <replaceable>expression</replaceable>