Re: NULL problem

Ti Lian Hwang (tilh@sin-co.sin-ro.DHL.COM) wrote: : If the value of b in the : select * from test where a = b : is a NULL , the select statment will not find anything, even though the : relevent record exists. See example below. [example deleted] : Is this a bug or a feature of 4GL :-) It's a "feature" of the SQL language, it has to do with 3-valued logic. The '=' operator returns a null truth value if either of its arguments are null. If you really want a single SQL statement, you could always use: select * from test where a = b or (a is null and b is null); but this might have a detrimental effect on your query performance, depending on how well Informix can optimize the disjunction. -- Jeff Sturm jsturm@mail.msen.com