Re: Null variables

Ehrmmmm! NULL = NULL yelds false? I'm afraid not :-) the result of the test is NULL, which is of course regarded as not being true by if & case statements, but is very far from being false... Ciao, Marco ______________________________________________________________________________ Marco Greco <marco@informix.com> Standard disclaimers apply! Informix faq http://www.iiug.org/techinfo/faq/informix.htm 4glworks http://www.ctonline.it/~marcog Informix on Linux http://www.ctonline.it/~marcog/ifmxlinux.htm jparker@epsilon.com wrote: > > NULL is special. NULL doesn't equal anything because it is by definition > undefined. So undefined != undefined (not true). Where ever you use NULL > you cannot use an equality or inequality statement. This leads to some > interesting things: > > NULL = NULL (false) > NULL != NULL (false) > NULL = foo (false) > NULL != foo (false) > > There is therefore a special test for NULL which does not involve an > equality statement - 'IS NULL'. > > IF a IS NULL THEN .... > > try to remember to use this power only for good. > > cheers > j. > > "Florin Micle" <florinmicle@gsc-mbh.de> on 08/12/98 12:44:22 PM > > Please respond to "Florin Micle" <florinmicle@gsc-mbh.de> > > To: informix-list@iiug.org > cc: (bcc: Jack Parker/Boston50/Epsilon) > Subject: Null variables > > Hi all, > Does anyone know how can I see if a passed variable into a stored > procedure in Informix (dbaccess) has null value? I can't compare it with > null because I get a syntax error (null - undeclared variable) if I pass > null value into another variable the evaluation of null = null returns > false! I wish it returned true... > Can anyone give me a solution for this? > Thanks, > Florin.