It's an excellent cookbook of useful SQL queries with well written explanations. I've used SQL for decades, but after reading a few articles, it was obvious that I could learn some new tricks. The articles are bite sized an tasty.
Sorry, it is wrong. SQL is not baſed on ſets, but bags, which are quite different and more complicated. And, by the way, CTEs are a feature of ISO SQL, not only of MS SQL Server.
Finally, entity‐relationſhip is not terribly practical as a model, but as diagrammiŋ.
Fans of this will probably also like Joe Celko's SQL for Smarties. ISBN: 0123693799
It's unfortunate that a lot of new programmers are relying on their framework's ORM to abstract the SQL away from them, weakening their understanding of it.