All of these notes were gathered from this excellent, free, in-depth SQL course, found here:

https://www.youtube.com/watch?v=SSKVgrwhzus

All the query examples in these notes use either of the two databases found by this link:

https://github.com/DataWithBaraa/sql-ultimate-course/tree/main/datasets/mysql

Would highly recommend using all that if you are learning SQL. Just to note, the original examples use SQL Server, but my notes cover the alternatives to use in MySQL.

Aside from that, this is partly serving as an extra backup for my notes, and partly to help anyone using my own databases for SQL practice.