Some articles are well worth reading twice.
I've spent all afternoon working for the first time with EXCEPT instead of the usual LEFT JOIN and checking for NULL, and it's taken half the keystrokes with no noticeable performance cost. Thanks!
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