CREATE OPERATOR
Synopsis
Use the CREATE OPERATOR statement to create an operator.
Syntax
create_operator ::= CREATE OPERATOR operator_name  ( 
                    { FUNCTION = subprogram_name
                      | PROCEDURE = subprogram_name } 
                    [ , operator_option [ ... ] ] )
operator_option ::= LEFTARG = left_type
                    | RIGHTARG = right_type
                    | COMMUTATOR = com_op
                    | NEGATOR = neg_op
                    | RESTRICT = res_proc
                    | JOIN = join_proc
                    | HASHES
                    | MERGES
Semantics
See the semantics of each option in the [PostgreSQL docs][postgresql-docs-create-operator].
Examples
Basic example.
yugabyte=# CREATE OPERATOR @#@ (
             rightarg = int8,
             procedure = numeric_fac
           );
yugabyte=# SELECT @#@ 5;
 ?column?
----------
      120