On Tue, 6 Apr 2010 16:22:01 -0700, CoralMelroe
wrote:

How do I add sales tax in my database query?

By using an appropriate expression.

For a more detailed answer please post a more detailed question, including
information such as the structure (fieldnames, datatypes) of your table,
whether you need to deal with multiple tax rates or just one, whether some
items or some customers are tax-exempt, what's the context (on a form, a
report, in a query...?)
--

John W. Vinson [MVP]