Re: Is This the varchar2 ZLS Issue?

A varchar2 datatype is not a string datatype. It is a variable length character field. Oracle treats a varchar2 column without a value as null.

The proper way to test for or specify the presence of data is to use the "IS NULL" or "IS NOT NULL" clauses.

where wo_request_date >= to_date('01-MAR-06') and wo_acct_no is null

Your second query fails because NULL <> NULL. Two unknowns are not equal!

HTH -- Mark D Powell -- Received on Sun Mar 19 2006 - 18:51:36 CST