What you are doing is generally a sensible approach but you need to view the Actual Execution Plan that Sql Server generates to see if they are being used by the Query Optimizer. There is a free pdf download from Red-Gate[^] that is very good. http://www.simple-talk.com/books/sql-books/sql-server-execution-plans/[^] If you are willing to spend some money, then buy this book. SQL Server 2008 Query Performance Tuning Distilled[^] I can't recommend this book highly enough. Although it is targeted at Sql2008, it's still very applicable to Sql2005 as well.