FROM and JOIN Build the Rows First

The first big step is `FROM` plus `JOIN`. SQL first decides which tables participate and how their rows connect.

Only after the joined row set exists does `WHERE` filter it.

That is why a query like this works:

SELECT e.name AS employee_name, d.name AS department_name
FROM employees AS e
JOIN departments AS d
  ON e.department_id = d.id
WHERE d.name = 'Engineering'

The `WHERE` clause can filter on department data because the `JOIN` has already happened logically.