On Thu, Jul 25, 2013 at 4:18 AM, Giuseppe Broccolo <giuseppe.broccolo@xxxxxxxxxxxxxx> wrote:
(TG_OP = 'UPDATE' AND
(NEW.b != OLD.b OR
(NEW.b IS NULL AND OLD.b IS NOT NULL) OR
(NEW.b IS NOT NULL AND OLD.b IS NULL)
)
) THEN
Unrelated to the OP's question, the suggestion above could be more simply rewritten as
TG_OP = 'UPDATE'
AND NEW.b IS DISTINCT FROM OLD.b
