Luis Cazares (10/22/2014)
Did you leave something out of your post? There seems to be no reason to have the 3 left joins in that query as it is.
Without DISTINCT, those left joins could generate dupes in the output, which, although unlikely, could be significant.
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