Understanding Relational Division in SQL

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.

Here is the code used in the example.

[vladghita]

Sir, thank you!

I admit I did not understand ... But I took the query and applied my entities ... And it works!

[var]

Thanks for your time and energy and your skill to demonstrate the relational division.

[bouchrab]

Thank you for this demo, this step by step helps a lot to understand this quite complex but very interesting query

[white_archive]

Thanks so much for the detailed explanation. It really helps a lot!

[oliversui]

Thanks for sharing this, it helps me a lot.

[toungewithgills]

How do you make a relationship in the database when building a dating website. When the relationship is more then just age, location, sexuality, likes, dislikes, when searching in a Query in the relational (relationship) in the database. Just started studying MYSQL still reading books, as well learning the functions available in MYSQL. Thank you for any response.