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CREATE OPERATOR(7)	PostgreSQL 9.6.3 Documentation	    CREATE OPERATOR(7)

NAME
       CREATE_OPERATOR - define	a new operator

SYNOPSIS
       CREATE OPERATOR name (
	   PROCEDURE = function_name
	   [, LEFTARG =	left_type ] [, RIGHTARG	= right_type ]
	   [, COMMUTATOR = com_op ] [, NEGATOR = neg_op	]
	   [, RESTRICT = res_proc ] [, JOIN = join_proc	]
	   [, HASHES ] [, MERGES ]
       )

DESCRIPTION
       CREATE OPERATOR defines a new operator, name. 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.

       The operator name is a sequence of up to	NAMEDATALEN-1 (63 by default)
       characters from the following list:

	   + - * / < > = ~ ! @ # % ^ & | ` ?

       There are a few restrictions on your choice of name:

       o   -- and /* cannot appear anywhere in an operator name, since they
	   will	be taken as the	start of a comment.

       o   A multicharacter operator name cannot end in	+ or -,	unless the
	   name	also contains at least one of these characters:

	       ~ ! @ # % ^ & | ` ?

	   For example,	@- is an allowed operator name,	but *- is not. This
	   restriction allows PostgreSQL to parse SQL-compliant	commands
	   without requiring spaces between tokens.

       o   The use of => as an operator	name is	deprecated. It may be
	   disallowed altogether in a future release.

       The operator != is mapped to <> on input, so these two names are	always
       equivalent.

       At least	one of LEFTARG and RIGHTARG must be defined. For binary
       operators, both must be defined.	For right unary	operators, only
       LEFTARG should be defined, while	for left unary operators only RIGHTARG
       should be defined.

       The function_name procedure must	have been previously defined using
       CREATE FUNCTION and must	be defined to accept the correct number	of
       arguments (either one or	two) of	the indicated types.

       The other clauses specify optional operator optimization	clauses. Their
       meaning is detailed in Section 36.13, "Operator Optimization
       Information", in	the documentation.

       To be able to create an operator, you must have USAGE privilege on the
       argument	types and the return type, as well as EXECUTE privilege	on the
       underlying function. If a commutator or negator operator	is specified,
       you must	own these operators.

PARAMETERS
       name
	   The name of the operator to be defined. See above for allowable
	   characters. The name	can be schema-qualified, for example CREATE
	   OPERATOR myschema.+ (...). 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
	   overloading.

       function_name
	   The function	used to	implement this operator.

       left_type
	   The data type of the	operator's left	operand, if any. This option
	   would be omitted for	a left-unary operator.

       right_type
	   The data type of the	operator's right operand, if any. This option
	   would be omitted for	a right-unary operator.

       com_op
	   The commutator of this operator.

       neg_op
	   The negator of this operator.

       res_proc
	   The restriction selectivity estimator function for this operator.

       join_proc
	   The join selectivity	estimator function for this operator.

       HASHES
	   Indicates this operator can support a hash join.

       MERGES
	   Indicates this operator can support a merge join.

       To give a schema-qualified operator name	in com_op or the other
       optional	arguments, use the OPERATOR() syntax, for example:

	   COMMUTATOR =	OPERATOR(myschema.===) ,

NOTES
       Refer to	Section	36.12, "User-defined Operators", in the	documentation
       for further information.

       It is not possible to specify an	operator's lexical precedence in
       CREATE OPERATOR,	because	the parser's precedence	behavior is
       hard-wired. See Section 4.1.6, "Operator	Precedence", in	the
       documentation for precedence details.

       The obsolete options SORT1, SORT2, LTCMP, and GTCMP 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 MERGES true.

       Use DROP	OPERATOR (DROP_OPERATOR(7)) to delete user-defined operators
       from a database.	Use ALTER OPERATOR (ALTER_OPERATOR(7)) to modify
       operators in a database.

EXAMPLES
       The following command defines a new operator, area-equality, for	the
       data type box:

	   CREATE OPERATOR === (
	       LEFTARG = box,
	       RIGHTARG	= box,
	       PROCEDURE = area_equal_procedure,
	       COMMUTATOR = ===,
	       NEGATOR = !==,
	       RESTRICT	= area_restriction_procedure,
	       JOIN = area_join_procedure,
	       HASHES, MERGES
	   );

COMPATIBILITY
       CREATE OPERATOR is a PostgreSQL extension. There	are no provisions for
       user-defined operators in the SQL standard.

SEE ALSO
       ALTER OPERATOR (ALTER_OPERATOR(7)), CREATE OPERATOR CLASS
       (CREATE_OPERATOR_CLASS(7)), DROP	OPERATOR (DROP_OPERATOR(7))

PostgreSQL 9.6.3		     2017		    CREATE OPERATOR(7)

NAME | SYNOPSIS | DESCRIPTION | PARAMETERS | NOTES | EXAMPLES | COMPATIBILITY | SEE ALSO

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