Mastering SQL Execution Order with JOINs

Mastering SQL Execution Order: How Queries Really Run Behind the Scenes

Last week we broke down SQL’s execution order: your clauses don’t run in the order you write them. FROM first, SELECT fifth.

You write SELECT first. SQL runs it fifth.

With one table, that’s easy to hold in your head. Add a JOIN, and one question trips up almost everyone: when you combine two tables and then filter them, what runs first?

The JOIN. It builds the combined table before any filter tou…