On Mon, 11 Mar 2002, Bhuvan A wrote: > here i have a problem in comparing null values in plpgsql. this exist > in 7.1.x and 7.2 as well. > > the condition <null value> != <valid value> fails in plpgsql. > consider this function is triggered on every updation on a table. > > create function ftest() > returns opaque as 'declare > > begin > > if new.comp_code != old.comp_code then > ... > end if; > return new; > end;' > language 'plpgsql'; > > this condition fails if old.comp_code is null and new.comp_code has > some value.
<nullvalue> != <anything> is not true, it's unknown, so the if shouldn't fire. It's a side effect of how the spec defines operations on nulls. ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
