1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>CREATE OPERATOR</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="sql-creatematerializedview.html" title="CREATE MATERIALIZED VIEW" /><link rel="next" href="sql-createopclass.html" title="CREATE OPERATOR CLASS" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">CREATE OPERATOR</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-creatematerializedview.html" title="CREATE MATERIALIZED VIEW">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-createopclass.html" title="CREATE OPERATOR CLASS">Next</a></td></tr></table><hr /></div><div class="refentry" id="SQL-CREATEOPERATOR"><div class="titlepage"></div><a id="id-1.9.3.72.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">CREATE OPERATOR</span></h2><p>CREATE OPERATOR — define a new operator</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
CREATE OPERATOR <em class="replaceable"><code>name</code></em> (
{FUNCTION|PROCEDURE} = <em class="replaceable"><code>function_name</code></em>
[, LEFTARG = <em class="replaceable"><code>left_type</code></em> ] [, RIGHTARG = <em class="replaceable"><code>right_type</code></em> ]
[, COMMUTATOR = <em class="replaceable"><code>com_op</code></em> ] [, NEGATOR = <em class="replaceable"><code>neg_op</code></em> ]
[, RESTRICT = <em class="replaceable"><code>res_proc</code></em> ] [, JOIN = <em class="replaceable"><code>join_proc</code></em> ]
[, HASHES ] [, MERGES ]
)
</pre></div><div class="refsect1" id="id-1.9.3.72.5"><h2>Description</h2><p>
<code class="command">CREATE OPERATOR</code> defines a new operator,
<em class="replaceable"><code>name</code></em>. The user who
defines an operator becomes its owner. If a schema name is given
then the operator is created in the specified schema. Otherwise it
is created in the current schema.
</p><p>
The operator name is a sequence of up to <code class="symbol">NAMEDATALEN</code>-1
(63 by default) characters from the following list:
</p><div class="literallayout"><p><br />
+ - * / < > = ~ ! @ # % ^ & | ` ?<br />
</p></div><p>
There are a few restrictions on your choice of name:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
<code class="literal">--</code> and <code class="literal">/*</code> cannot appear anywhere in an operator name,
since they will be taken as the start of a comment.
</p></li><li class="listitem"><p>
A multicharacter operator name cannot end in <code class="literal">+</code> or
<code class="literal">-</code>,
unless the name also contains at least one of these characters:
</p><div class="literallayout"><p><br />
~ ! @ # % ^ & | ` ?<br />
</p></div><p>
For example, <code class="literal">@-</code> is an allowed operator name,
but <code class="literal">*-</code> is not.
This restriction allows <span class="productname">PostgreSQL</span> to
parse SQL-compliant commands without requiring spaces between tokens.
</p></li><li class="listitem"><p>
The symbol <code class="literal">=></code> is reserved by the SQL grammar,
so it cannot be used as an operator name.
</p></li></ul></div><p>
</p><p>
The operator <code class="literal">!=</code> is mapped to
<code class="literal"><></code> on input, so these two names are always
equivalent.
</p><p>
For binary operators, both <code class="literal">LEFTARG</code> and
<code class="literal">RIGHTARG</code> must be defined. For prefix operators only
<code class="literal">RIGHTARG</code> should be defined.
The <em class="replaceable"><code>function_name</code></em>
function must have been previously defined using <code class="command">CREATE
FUNCTION</code> and must be defined to accept the correct number
of arguments (either one or two) of the indicated types.
</p><p>
In the syntax of <code class="literal">CREATE OPERATOR</code>, the keywords
<code class="literal">FUNCTION</code> and <code class="literal">PROCEDURE</code> are
equivalent, but the referenced function must in any case be a function, not
a procedure. The use of the keyword <code class="literal">PROCEDURE</code> here is
historical and deprecated.
</p><p>
The other clauses specify optional operator optimization clauses.
Their meaning is detailed in <a class="xref" href="xoper-optimization.html" title="38.15. Operator Optimization Information">Section 38.15</a>.
</p><p>
To be able to create an operator, you must have <code class="literal">USAGE</code>
privilege on the argument types and the return type, as well
as <code class="literal">EXECUTE</code> privilege on the underlying function. If a
commutator or negator operator is specified, you must own these operators.
</p></div><div class="refsect1" id="id-1.9.3.72.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>name</code></em></span></dt><dd><p>
The name of the operator to be defined. See above for allowable
characters. The name can be schema-qualified, for example
<code class="literal">CREATE OPERATOR myschema.+ (...)</code>. If not, then
the operator is created in the current schema. Two operators
in the same schema can have the same name if they operate on
different data types. This is called
<em class="firstterm">overloading</em>.
</p></dd><dt><span class="term"><em class="replaceable"><code>function_name</code></em></span></dt><dd><p>
The function used to implement this operator.
</p></dd><dt><span class="term"><em class="replaceable"><code>left_type</code></em></span></dt><dd><p>
The data type of the operator's left operand, if any.
This option would be omitted for a prefix operator.
</p></dd><dt><span class="term"><em class="replaceable"><code>right_type</code></em></span></dt><dd><p>
The data type of the operator's right operand.
</p></dd><dt><span class="term"><em class="replaceable"><code>com_op</code></em></span></dt><dd><p>
The commutator of this operator.
</p></dd><dt><span class="term"><em class="replaceable"><code>neg_op</code></em></span></dt><dd><p>
The negator of this operator.
</p></dd><dt><span class="term"><em class="replaceable"><code>res_proc</code></em></span></dt><dd><p>
The restriction selectivity estimator function for this operator.
</p></dd><dt><span class="term"><em class="replaceable"><code>join_proc</code></em></span></dt><dd><p>
The join selectivity estimator function for this operator.
</p></dd><dt><span class="term"><code class="literal">HASHES</code></span></dt><dd><p>
Indicates this operator can support a hash join.
</p></dd><dt><span class="term"><code class="literal">MERGES</code></span></dt><dd><p>
Indicates this operator can support a merge join.
</p></dd></dl></div><p>
To give a schema-qualified operator name in <em class="replaceable"><code>com_op</code></em> or the other optional
arguments, use the <code class="literal">OPERATOR()</code> syntax, for example:
</p><pre class="programlisting">
COMMUTATOR = OPERATOR(myschema.===) ,
</pre></div><div class="refsect1" id="id-1.9.3.72.7"><h2>Notes</h2><p>
Refer to <a class="xref" href="xoper.html" title="38.14. User-Defined Operators">Section 38.14</a> for further information.
</p><p>
It is not possible to specify an operator's lexical precedence in
<code class="command">CREATE OPERATOR</code>, because the parser's precedence behavior
is hard-wired. See <a class="xref" href="sql-syntax-lexical.html#SQL-PRECEDENCE" title="4.1.6. Operator Precedence">Section 4.1.6</a> for precedence details.
</p><p>
The obsolete options <code class="literal">SORT1</code>, <code class="literal">SORT2</code>,
<code class="literal">LTCMP</code>, and <code class="literal">GTCMP</code> were formerly used to
specify the names of sort operators associated with a merge-joinable
operator. This is no longer necessary, since information about
associated operators is found by looking at B-tree operator families
instead. If one of these options is given, it is ignored except
for implicitly setting <code class="literal">MERGES</code> true.
</p><p>
Use <a class="link" href="sql-dropoperator.html" title="DROP OPERATOR"><code class="command">DROP OPERATOR</code></a> to delete user-defined operators
from a database. Use <a class="link" href="sql-alteroperator.html" title="ALTER OPERATOR"><code class="command">ALTER OPERATOR</code></a> to modify operators in a
database.
</p></div><div class="refsect1" id="id-1.9.3.72.8"><h2>Examples</h2><p>
The following command defines a new operator, area-equality, for
the data type <code class="type">box</code>:
</p><pre class="programlisting">
CREATE OPERATOR === (
LEFTARG = box,
RIGHTARG = box,
FUNCTION = area_equal_function,
COMMUTATOR = ===,
NEGATOR = !==,
RESTRICT = area_restriction_function,
JOIN = area_join_function,
HASHES, MERGES
);
</pre></div><div class="refsect1" id="id-1.9.3.72.9"><h2>Compatibility</h2><p>
<code class="command">CREATE OPERATOR</code> is a
<span class="productname">PostgreSQL</span> extension. There are no
provisions for user-defined operators in the SQL standard.
</p></div><div class="refsect1" id="id-1.9.3.72.10"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-alteroperator.html" title="ALTER OPERATOR"><span class="refentrytitle">ALTER OPERATOR</span></a>, <a class="xref" href="sql-createopclass.html" title="CREATE OPERATOR CLASS"><span class="refentrytitle">CREATE OPERATOR CLASS</span></a>, <a class="xref" href="sql-dropoperator.html" title="DROP OPERATOR"><span class="refentrytitle">DROP OPERATOR</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-creatematerializedview.html" title="CREATE MATERIALIZED VIEW">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-createopclass.html" title="CREATE OPERATOR CLASS">Next</a></td></tr><tr><td width="40%" align="left" valign="top">CREATE MATERIALIZED VIEW </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="40%" align="right" valign="top"> CREATE OPERATOR CLASS</td></tr></table></div></body></html>
|
