Re: Informix 4gl infant question

Mike Rogoff (miker@nit.airtouch.com) wrote: : Hi, if anyone could help me with the following question it would be : much appreciated (it's probably trivial). : In a query comparing column names in a table to program variables : (with '='), the query seems to fail when the program variables are : NULL. Even if the column is null, the query doesn't match the row. : (Data type is char[]). : Thanks..... Hi Mike: By definition, all comparisons with NULL values are false. You need to use the "IS NULL" keywords: Ex. define input_code char(6) ... code to input the code if input_code is not null then select cust_code from customers where cust_code = input_code else select cust_code from customers where cust_code is null end if Hope this helps. -- /************************************************************** * Ryan McFall * * Dept. of Computer Science * * Michigan State University * * mcfallry@cps.msu.edu * * * * My statments do not reflect the opinions of MSU, * * Heck, they probably don't even make sense! * *************************************************************/