Roy, I neglected to say "nice article" in my previous post.... Thanks, I did enjoy it!

jcrawf02, that was true a long time ago, but for many years now SQL Server's optimizer can tell when a query is just checking for existence and makes no attempt to retrieve all the column values if it doesn't have to. You can see for yourself by checking query plans, they'll be identical for IF EXISTS(SELECT * from ...) and for IF EXISTS (SELECT col1 from ...) and for IF EXISTS (SELECT 1 from ...). If you're doing something else beyond simply checking for existence, however, I think your instructor's position is correct.