GROUP BY and result grain
Choosing the grouping keys that produce the grain the question actually asks for, and recognising when a result is at the wrong grain.
We mark it against a checklist you can read first
What counts as knowing this
State the grain of a result set and write the GROUP BY that produces it
A 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.
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What it unlocks
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.
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