Lynn Pettis (9/17/2012)
Start here: http://msdn.microsoft.com/en-us/library/ms177410(v=sql.90).aspx
When you've read through that, read this excellent alternative by Dwain Camps[/url].
For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden