Notes/errata/updates for Chapter 7:
See the official book errata at http://tahaghoghi.com/LearningMySQL/errata.php – Chapter 7 includes pages 223 – 275.
Supplemental blog post – ORDER BY NULL – read the blog post and the comments!
GROUP BY and HAVING examples – Supplemental blog post. The example of HAVING in the text shows a use case where HAVING is the same function as WHERE. This blog posts shows examples of HAVING that you cannot do any other way.
In the section called “The GROUP BY clause”, on pages 231-232,
the book says:
“you can count any column in a group, and you’ll get the same answer, so COUNT(artist_name) is the same as …