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Commit bb18b473 authored by Bruce Momjian's avatar Bruce Momjian
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Document partial indexes for IS NULL lookups.

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<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.45 2004/04/20 01:00:26 momjian Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.46 2004/04/20 04:25:47 momjian Exp $
PostgreSQL documentation
-->
......@@ -77,11 +77,9 @@ CREATE [ UNIQUE ] INDEX <replaceable class="parameter">name</replaceable> ON <re
</para>
<para>
<literal>NULL</> values are not indexed by default. The best way
to index <literal>NULL</> values is to create a partial index using
an <literal>IS NULL</> comparison. <literal>IS NULL</> is more
of a function call than a value comparison, and this is why a partial
index works.
Indexes can not be used with <literal>IS NULL</> clauses by default.
The best way to use indexes in such cases is to create a partial index
using an <literal>IS NULL</> comparison.
</para>
<para>
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