I included some definitions and explanations in some of the .sql files, as well as added some additional comments/notes on certain topics. I use pgAdmin3 (1.22) and PostgreSQL 9.5 to "Execute arbitrary SQL queries," and comment out all non-code (definitions, explanations, etc...) and previous queries, using the asterisk block comment. This allows me to have a single continuous file of query code and pertinent information for each chapter without improperly executing the previous queries.
I find the best way for me to learn is to rewrite, or in this case type out, as much of the info as you can. So, I ended up with a fairly large word document, roughly outlining the book as I went through.
This mostly is a code-along and outline of, "Practical_SQL A Beginner's Guide to Storytelling with Data" - By Anthony DeBarros. The chapter structure and examples are straight from the text.