On Mon, 11 Mar 2002, Bhuvan A wrote:
> > > On Mar 10, Stephan Szabo wrote: > > > 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 > > what do you mean by <nullvalue> != <anything>? If you compare a NULL with anything you don't get a true value whether you're comparing with =, !=, <, >, etc... That's how it's defined to behave. ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html
