HAVING vs WHERE

Filtering before aggregation versus after it, and the performance and correctness consequences of each.

core~1hWe mark it against a checklist you can read first

The barWhat counts as knowing this

Choose correctly between filtering rows and filtering groups, and say why

That sentence is the bar. It only counts once your work shows you can do it. Reading about it does not.

Prove itA check for this one skill

Up to 2 questions on this skill alone, marked against the bar beside this. It stops as soon as the answer is clear. No account, and your answers are not kept.

01 · Prerequisites

You'll need these first

Filtering with WHERE
GROUP BY and result grain

Start on SQL & Data Analysis

Every skill above, ordered by what depends on what, with the projects above that as the evidence you actually did it. We work out where you already are first, so the path skips what you can do.

About three minutes to set up. Nothing is marked until you hand something in.Start this path

Part of SQL & Data Analysis.