Practical PostgreSQL

Create Operator

Defines a new operator within the database.

Synopsis

CREATE OPERATOR name ( PROCEDURE = func_name
      [, LEFTARG = type1 ] [, RIGHTARG = type2 ]
      [, COMMUTATOR = com_op ] [, NEGATOR = neg_op ]
      [, RESTRICT = res_proc ] [, JOIN = join_proc ]
      [, HASHES ] [, SORT1 = left_sort_op ] [, SORT2 = right_sort_op ] )

Parameters

name

The character sequence of the new operator. Read further for a list of valid characters to use in names and symbols.

func_name

The function that implements the new operator.

type1

The type of the left-hand argument. Do not use this option with a unary operator that always appears to the left of the value on which it operates.

type2

The data type of the right-hand argument. Do not use this option with a unary operator that always appears to the right of the value on which it operates.

com_op

The commutator operator for the new operator. A commutator is another existing operator which executes the commutation (order reversal) of the procedure defined for the new operator, e.g., with the left argument treated as the right argument, and the right argument treated as the left argument.

neg_op

The negator operator for the new operator. A negator is another existing operator which executes the literal inversion of the procedure define for the new operator. A negator should only be defined if the result of applying the NOT keyword to the new operator always results in the same output that the negator would return on the same condition.

res_proc

The name of the restriction selectivity ...