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Mention that LIKE ... ESCAPE '' is allowed to specify no 

escape character.
This commit is contained in:
Tom Lane 2001-11-18 21:17:10 +00:00
parent 98e05cec5b
commit deab49566d
1 changed files with 15 additions and 4 deletions
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19
doc/src/sgml/func.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.79 2001/11/17 22:20:33 tgl Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.80 2001/11/18 21:17:10 tgl Exp $
Postgres documentation
-->
@ -1228,8 +1228,19 @@ Postgres documentation
<para>
Note that the backslash already has a special meaning in string
literals, so to write a pattern constant that contains a backslash
you must write two backslashes in the query. You can avoid this by
selecting a different escape character with <literal>ESCAPE</literal>.
you must write two backslashes in the query. Thus, writing a pattern
that actually matches a literal backslash means writing four backslashes
in the query. You can avoid this by selecting a different escape
character with <literal>ESCAPE</literal>; then backslash isn't special
to <function>LIKE</> anymore. (But it's still special to the string
literal parser, so you still need two of them.)
</para>
<para>
It's also possible to select no escape character by writing
<literal>ESCAPE ''</literal>. In this case there is no way to
turn off the special meaning of underscore and percent signs in
the pattern.
</para>
<para>
@ -1245,7 +1256,7 @@ Postgres documentation
<function>ILIKE</function>. There are also
<literal>!~~</literal> and <literal>!~~*</literal> operators that
represent <function>NOT LIKE</function> and <function>NOT
ILIKE</function>. All of these are also
ILIKE</function>. All of these operators are
<productname>Postgres</productname>-specific.
</para>
</sect2>