Neither do I Greg and that’s an excellent point you’ve made.
An article claiming to list the required skill set for a general-purpose TSQL developer, published here on ssc, absolutely has to be first-rate.
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