Intermediate level SQL on Relational Division using GROUP BY, COUNT, HAVING, and a correlated subquery or common table expression (CTE). A simple example, stripped-down example of Job Applicants with certain Skills, and Jobs that require certain skills is provided to teach the concept of relational division.

Here is the script to create the example JobSkills database, with data.
https://douglaskline.blogspot.com/201...

Here is the code used in the example.
https://douglaskline.blogspot.com/201...