The pg_operator system catalog table stores information about operators, both built-in and those defined by CREATE OPERATOR. Unused column contain zeroes. For example, oprleft is zero for a prefix operator.

    column type references description
    oid oid Row identifier (hidden attribute, must be explicityly selected)
    oprname name Name of the operator
    oprnamespace oid pg_namespace.oid The OID of the namespace that contains this operator
    oprowner oid pg_authid.oid Owner of the operator
    oprkind char b = infix (both), l = prefix (left), r = postfix (right)
    oprcanmerge boolean This operator supports merge joins
    oprcanhash boolean This operator supports hash joins
    oprleft oid pg_type.oid Type of the left operand
    oprright oid pg_type.oid Type of the right operand
    oprresult oid pg_type.oid Type of the result
    oprcom oid pg_operator.oid Commutator of this operator, if any
    oprnegate oid pg_operator.oid Negator of this operator, if any
    oprcode regproc pg_proc.oid Function that implements this operator
    oprrest regproc pg_proc.oid Restriction selectivity estimation function for this operator
    oprjoin regproc pg_proc.oid Join selectivity estimation function for this operator

    Parent topic: System Catalogs Definitions