Part 2 of "Intentional, or a bug"....

Hi again.

First of all, tank you for the immediate and precise answers.

My solution to the problem was the following. However, I found
that to be quite slow. I would like to ask if one can suggest me
how to optimize this, because I need this regularly.

CREATE FUNCTION gyegyenlo(text, text) RETURNS boolean AS ' SELECT CASE WHEN $1 is null and $2 is null THEN true
                        ELSE ($1) = ($2)      END;
 
' LANGUAGE 'sql';

CREATE OPERATOR ~= ( leftarg = text, rightarg = text, procedure = gyegyenlo, commutator = ~=
);

After these I use ~= if I need lines with NULLs in both to be selected.

The only problem is that it makes the query very slow. Does anyone
knows how to optimize this?

Thanks,
Baldvin