CREATE OPERATOR -- define a new operator
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 ]
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:
-- and /* cannot appear anywhere in an operator name,
since they will be taken as the start of a comment.
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.
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
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.
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 35.13.
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
The function used to implement this operator.
The data type of the operator's left operand, if any.
This option would be omitted for a left-unary operator.
The data type of the operator's right operand, if any.
This option would be omitted for a right-unary operator.
The commutator of this operator.
The negator of this operator.
The restriction selectivity estimator function for this operator.
The join selectivity estimator function for this operator.
Indicates this operator can support a hash join.
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.===) ,
Refer to Section 35.12 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 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 to delete user-defined operators
from a database. Use ALTER OPERATOR to modify operators in a
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,
CREATE OPERATOR is a
PostgreSQL extension. There are no
provisions for user-defined operators in the SQL standard.