Greg Fischer wrote:
> Hello all!
> I do my best to read and google my way around issues, but I seem to be
> missing something. Probably simple too.
>
> So I have a trigger function, in which I'd like to check if a particular
> column has changed. It works great, unless either the OLD or NEW values
> are NULL. The purpose is to create a audit/log of the record. I prefer
> to only test for certain columns, not the whole table.
>
>
> CREATE OR REPLACE FUNCTION tr_employees_bu()
> RETURNS trigger AS
> $BODY$
> begin
> if (new.trainingdate <> old.trainingdate) then
Instead, try the test:
new.trainingdate IS DISTINCT FROM old.trainingdate
See the manual for 'IS DISTINCT FROM'.
--
Craig Ringer