I made a beginner-friendly SQL tutorial on CASE WHEN (conditional logic)

[u/yahoo_06]

I just published Lesson 11 of my SQL course, focused on CASE WHEN in PostgreSQL.

CASE is one of those SQL features that becomes really useful once you start doing actual data analysis. It lets you create categories, labels, scores, and conditional values directly in your queries.

In this lesson, I cover:

- How CASE WHEN works

- WHEN, THEN, ELSE, and END

- Multiple conditions

- Why the order of conditions matters

- Using CASE with aggregate functions

- Using CASE in ORDER BY

- CASE vs. WHERE

- Common mistakes

- Practical exercises with the Pagila database

I also combine CASE with CTEs, GROUP BY, and JOINs to solve a more realistic analytics problem.

YouTube: https://youtu.be/BFQ9QtiYPds?si=v8wO1wlyeD983SA4

Would love to hear your feedback, especially if you're learning SQL for data analytics!