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  1. <?xml version="1.0" encoding="UTF-8" standalone="no"?>

  2. <!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 V1.79.1" /><link rel="prev" href="sql-creatematerializedview.html" title="CREATE MATERIALIZED VIEW" /><link rel="next" href="sql-createopclass.html" title="CREATE OPERATOR CLASS" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" 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 12.4 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></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">

  3. CREATE OPERATOR <em class="replaceable"><code>name</code></em> (

  4.     {FUNCTION|PROCEDURE} = <em class="replaceable"><code>function_name</code></em>

  5.     [, LEFTARG = <em class="replaceable"><code>left_type</code></em> ] [, RIGHTARG = <em class="replaceable"><code>right_type</code></em> ]

  6.     [, COMMUTATOR = <em class="replaceable"><code>com_op</code></em> ] [, NEGATOR = <em class="replaceable"><code>neg_op</code></em> ]

  7.     [, RESTRICT = <em class="replaceable"><code>res_proc</code></em> ] [, JOIN = <em class="replaceable"><code>join_proc</code></em> ]

  8.     [, HASHES ] [, MERGES ]

  9. )

  10. </pre></div><div class="refsect1" id="id-1.9.3.72.5"><h2>Description</h2><p>

  11.    <code class="command">CREATE OPERATOR</code> defines a new operator,

  12.    <em class="replaceable"><code>name</code></em>.  The user who

  13.    defines an operator becomes its owner.  If a schema name is given

  14.    then the operator is created in the specified schema.  Otherwise it

  15.    is created in the current schema.

  16.   </p><p>

  17.    The operator name is a sequence of up to <code class="symbol">NAMEDATALEN</code>-1

  18.    (63 by default) characters from the following list:

  19. </p><div class="literallayout"><p><br />

  20. + - * / &lt; &gt; = ~ ! @ # % ^ &amp; | ` ?<br />

  21. </p></div><p>

  22. 

  23.    There are a few restrictions on your choice of name:

  24.    </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,

  25.      since they will be taken as the start of a comment.

  26.      </p></li><li class="listitem"><p>

  27.      A multicharacter operator name cannot end in <code class="literal">+</code> or

  28.      <code class="literal">-</code>,

  29.      unless the name also contains at least one of these characters:

  30. </p><div class="literallayout"><p><br />

  31. ~ ! @ # % ^ &amp; | ` ?<br />

  32. </p></div><p>

  33.      For example, <code class="literal">@-</code> is an allowed operator name,

  34.      but <code class="literal">*-</code> is not.

  35.      This restriction allows <span class="productname">PostgreSQL</span> to

  36.      parse SQL-compliant commands without requiring spaces between tokens.

  37.      </p></li><li class="listitem"><p>

  38.      The use of <code class="literal">=&gt;</code> as an operator name is deprecated.  It may

  39.      be disallowed altogether in a future release.

  40.      </p></li></ul></div><p>

  41.   </p><p>

  42.    The operator <code class="literal">!=</code> is mapped to

  43.    <code class="literal">&lt;&gt;</code> on input, so these two names are always

  44.    equivalent.

  45.   </p><p>

  46.    At least one of <code class="literal">LEFTARG</code> and <code class="literal">RIGHTARG</code> must be defined.  For

  47.    binary operators, both must be defined. For right  unary

  48.    operators, only <code class="literal">LEFTARG</code> should be defined, while for left

  49.    unary operators only <code class="literal">RIGHTARG</code> should be defined.

  50.   </p><p>

  51.    The <em class="replaceable"><code>function_name</code></em>

  52.    function must have been previously defined using <code class="command">CREATE

  53.    FUNCTION</code> and must be defined to accept the correct number

  54.    of arguments (either one or two) of the indicated types.

  55.   </p><p>

  56.    In the syntax of <code class="literal">CREATE OPERATOR</code>, the keywords

  57.    <code class="literal">FUNCTION</code> and <code class="literal">PROCEDURE</code> are

  58.    equivalent, but the referenced function must in any case be a function, not

  59.    a procedure.  The use of the keyword <code class="literal">PROCEDURE</code> here is

  60.    historical and deprecated.

  61.   </p><p>

  62.    The other clauses specify optional operator optimization clauses.

  63.    Their meaning is detailed in <a class="xref" href="xoper-optimization.html" title="37.15. Operator Optimization Information">Section 37.15</a>.

  64.   </p><p>

  65.    To be able to create an operator, you must have <code class="literal">USAGE</code>

  66.    privilege on the argument types and the return type, as well

  67.    as <code class="literal">EXECUTE</code> privilege on the underlying function.  If a

  68.    commutator or negator operator is specified, you must own these operators.

  69.   </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>

  70.         The name of the operator to be defined. See above for allowable

  71.         characters.  The name can be schema-qualified, for example

  72.         <code class="literal">CREATE OPERATOR myschema.+ (...)</code>.  If not, then

  73.         the operator is created in the current schema.  Two operators

  74.         in the same schema can have the same name if they operate on

  75.         different data types.  This is called

  76.         <em class="firstterm">overloading</em>.

  77.        </p></dd><dt><span class="term"><em class="replaceable"><code>function_name</code></em></span></dt><dd><p>

  78.         The function used to implement this operator.

  79.        </p></dd><dt><span class="term"><em class="replaceable"><code>left_type</code></em></span></dt><dd><p>

  80.         The data type of the operator's left operand, if any.

  81.         This option would be omitted for a left-unary operator.

  82.        </p></dd><dt><span class="term"><em class="replaceable"><code>right_type</code></em></span></dt><dd><p>

  83.         The data type of the operator's right operand, if any.

  84.         This option would be omitted for a right-unary operator.

  85.        </p></dd><dt><span class="term"><em class="replaceable"><code>com_op</code></em></span></dt><dd><p>

  86.         The commutator of this operator.

  87.        </p></dd><dt><span class="term"><em class="replaceable"><code>neg_op</code></em></span></dt><dd><p>

  88.         The negator of this operator.

  89.        </p></dd><dt><span class="term"><em class="replaceable"><code>res_proc</code></em></span></dt><dd><p>

  90.         The restriction selectivity estimator function for this operator.

  91.        </p></dd><dt><span class="term"><em class="replaceable"><code>join_proc</code></em></span></dt><dd><p>

  92.         The join selectivity estimator function for this operator.

  93.        </p></dd><dt><span class="term"><code class="literal">HASHES</code></span></dt><dd><p>

  94.        Indicates this operator can support a hash join.

  95.        </p></dd><dt><span class="term"><code class="literal">MERGES</code></span></dt><dd><p>

  96.        Indicates this operator can support a merge join.

  97.        </p></dd></dl></div><p>

  98.    To give a schema-qualified operator name in <em class="replaceable"><code>com_op</code></em> or the other optional

  99.    arguments, use the <code class="literal">OPERATOR()</code> syntax, for example:

  100. </p><pre class="programlisting">

  101. COMMUTATOR = OPERATOR(myschema.===) ,

  102. </pre></div><div class="refsect1" id="id-1.9.3.72.7"><h2>Notes</h2><p>

  103.    Refer to <a class="xref" href="xoper.html" title="37.14. User-Defined Operators">Section 37.14</a> for further information.

  104.   </p><p>

  105.    It is not possible to specify an operator's lexical precedence in

  106.    <code class="command">CREATE OPERATOR</code>, because the parser's precedence behavior

  107.    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.

  108.   </p><p>

  109.    The obsolete options <code class="literal">SORT1</code>, <code class="literal">SORT2</code>,

  110.    <code class="literal">LTCMP</code>, and <code class="literal">GTCMP</code> were formerly used to

  111.    specify the names of sort operators associated with a merge-joinable

  112.    operator.  This is no longer necessary, since information about

  113.    associated operators is found by looking at B-tree operator families

  114.    instead.  If one of these options is given, it is ignored except

  115.    for implicitly setting <code class="literal">MERGES</code> true.

  116.   </p><p>

  117.    Use <a class="xref" href="sql-dropoperator.html" title="DROP OPERATOR"><span class="refentrytitle">DROP OPERATOR</span></a> to delete user-defined operators

  118.    from a database.  Use <a class="xref" href="sql-alteroperator.html" title="ALTER OPERATOR"><span class="refentrytitle">ALTER OPERATOR</span></a> to modify operators in a

  119.    database.

  120.   </p></div><div class="refsect1" id="id-1.9.3.72.8"><h2>Examples</h2><p>

  121.    The following command defines a new operator, area-equality, for

  122.    the data type <code class="type">box</code>:

  123. </p><pre class="programlisting">

  124. CREATE OPERATOR === (

  125.     LEFTARG = box,

  126.     RIGHTARG = box,

  127.     FUNCTION = area_equal_function,

  128.     COMMUTATOR = ===,

  129.     NEGATOR = !==,

  130.     RESTRICT = area_restriction_function,

  131.     JOIN = area_join_function,

  132.     HASHES, MERGES

  133. );

  134. </pre></div><div class="refsect1" id="id-1.9.3.72.9"><h2>Compatibility</h2><p>

  135.    <code class="command">CREATE OPERATOR</code> is a

  136.    <span class="productname">PostgreSQL</span> extension.  There are no

  137.    provisions for user-defined operators in the SQL standard.

  138.   </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">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-createopclass.html">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">Home</a></td><td width="40%" align="right" valign="top"> CREATE OPERATOR CLASS</td></tr></table></div></body></html>
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