That may be an unrestricted update. The left-joined table contributes nothing, and the WHERE clause is an unpredictable mess of AND and OR. What exactly are you trying to do?
For better assistance in answering your questions, please read this[/url].
Hidden RBAR: Triangular Joins[/url] / The "Numbers" or "Tally" Table: What it is and how it replaces a loop[/url] Jeff Moden[/url]