Switching alias in subquery equality leads to different result

Trying to learn sql queries recently and as the title says I stumbled upon some "behavior" i didn't understand. This query returns the managers from the database. SELECT * FROM employees e WHERE EXISTS (SELECT * FROM employees f WHERE e.employee_id = f.manager_id) However if I switch the aliases in the equality it returns all the employees. SELECT * FROM employees e WHERE EXISTS (SELECT * FROM employees f WHERE f.employee_id = e.manager_id) Isn't employees e and employees f the same table but with different names? If so, why is then the alias order important?