Check Constraint Question

Hi Experts!

        Can a check constraint include a null value? I have a requirement to add a check constraint to a column with a two-digit "type". The column can be null, but if it has a value is has to be one of the specified values.

        For example, the requirements state values can be "AB, BC, CD, DE, with a null indicating type AB". All the examples of check constraints I've seen don't show a null value allowed. Would I say something like ... values in ('AB','BC','CD','DE',NULL)... or is this even possible? If it IS possible, how would the syntax look?

Thanks in advance,

Tamara Swilley
AGENCY.COM-Avon
tswilley_at_agency.com Received on Tue Sep 26 2000 - 18:16:51 CDT