Provided by: postgresql-client-9.1_9.1.3-2_i386
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
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.
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 35.13, “Operator Optimization
Information”, in the documentation.
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, “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.
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.
ALTER OPERATOR (ALTER_OPERATOR(7)), CREATE OPERATOR CLASS
(CREATE_OPERATOR_CLASS(7)), DROP OPERATOR (DROP_OPERATOR(7))