On Tuesday 21 April 2009 14:04:01 fduerr wrote:
> CREATE OR REPLACE FUNCTION eq_int_bool(INTEGER, BOOLEAN) RETURNS BOOLEAN AS
> 'SELECT CAST($1 AS BOOLEAN)=$2;' LANGUAGE SQL IMMUTABLE;
> CREATE OPERATOR = (
> LEFTARG=INTEGER,
> RIGHTARG=BOOLEAN,
> PROCEDURE=eq_int_bool,
> COMMUTATOR= = ,
> NEGATOR= <>
> );
>
> And thats, what i got:
>
> SELECT 1=false;
> ?column?
> ----------
> f
> (1 row)
>
> SELECT 1<>false;
> 8.3.x: ERROR: cache lookup failed for function 0
> 8.4b1: ERROR: operator is only a shell: integer <> boolean
>
> The workaround is, of course, to define an operator with '<>' as commutator
> that returns the negated result. Still i wonder: is it me, the
> documentation or pg?
What you did above is to specify which operator is the negator of =. But you
still need to create that operator; it is not created automatically.
