Hi Guys, There are some difficulties when you want to use the SQL Query mode in Access since they fully supports all the functions using UIs......... So I hope that following links may help you up to some extent. Queries - http://office.microsoft.com/en-us/access/CH100645771033.aspx Constraints - http://office.microsoft.com/en-us/access/CH063655121033.aspx Constraint Clause - http://office.microsoft.com/en-us/access/HA012314371033.aspx?pid=CH100728991033 Have fun guys,