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authorTom Lane <tgl@sss.pgh.pa.us>2020-03-23 12:42:16 -0400
committerTom Lane <tgl@sss.pgh.pa.us>2020-03-23 12:42:16 -0400
commit2af8894c409d0464d4f29449ac39d7d229ccc6ef (patch)
tree58707038c31d1deee487318edb92762fc9db3e4c
parent5f9eace5db4ef9d020aef44f972cea627b663932 (diff)
downloadpostgresql-2af8894c409d0464d4f29449ac39d7d229ccc6ef.tar.gz
postgresql-2af8894c409d0464d4f29449ac39d7d229ccc6ef.zip
Doc: explain that LIKE et al can be used in ANY (sub-select) etc.
This wasn't stated anywhere, and it's perhaps not that obvious, since we get questions about it from time to time. Also undocumented was that the parser actually translates these into operators. Discussion: https://postgr.es/m/CAFj8pRBkvZ71BqGKZnBBG4=0cKG+s50Dy+DYmrizUKEpAtdc+w@mail.gmail.com
-rw-r--r--doc/src/sgml/func.sgml18
1 files changed, 17 insertions, 1 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f196c6bc8bd..e356774586b 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -3709,7 +3709,23 @@ cast(-44 as bit(12)) <lineannotation>111111010100</lineannotation>
<literal>!~~</literal> and <literal>!~~*</literal> operators that
represent <function>NOT LIKE</function> and <function>NOT
ILIKE</function>, respectively. All of these operators are
- <productname>PostgreSQL</productname>-specific.
+ <productname>PostgreSQL</productname>-specific. You may see these
+ operator names in <command>EXPLAIN</command> output and similar
+ places, since the parser actually translates <function>LIKE</function>
+ et al. to these operators.
+ </para>
+
+ <para>
+ The phrases <function>LIKE</function>, <function>ILIKE</function>,
+ <function>NOT LIKE</function>, and <function>NOT ILIKE</function> are
+ generally treated as operators
+ in <productname>PostgreSQL</productname> syntax; for example they can
+ be used in <replaceable>expression</replaceable>
+ <replaceable>operator</replaceable> ANY
+ (<replaceable>subquery</replaceable>) constructs, although
+ an <literal>ESCAPE</literal> clause cannot be included there. In some
+ obscure cases it may be necessary to use the underlying operator names
+ instead.
</para>
</sect2>