It works, shouldn´t but works. Results False And I have created these two operators a long time ago. CREATE OPERATOR public.= ( FUNCTION = public.fntextonumero, LEFTARG = text, RIGHTARG = public.i32 ); CREATE OPERATOR public.= ( FUNCTION = public.fntextonumero, LEFTARG = public.i32, RIGHTARG = text ); Droped them and works as expected, giving me same message like yours. DROP OPERATOR public.= (text,public.i32); DROP OPERATOR public.= (public.i32,text); -- Sent from: https://www.postgresql-archive.org/PostgreSQL-general-f1843780.html