Subqueries vs CTEs: When, Why, How.

With a background in Python programming, Learning SQL started feeling like a step back, every line is independent of the next and so far nothing seemed interconnected or Programming-like, until I hit a wall: Picture this : You have a table employees and you need to find employees who earn more than the average salary of their own department, not the company average. This Problem requires two queries, one to get the average salary of each department and another to find the employee whose salary i