Case rounds
Atterna Foundations
You can write a query and want to defend the number it gives
Case rounds: Cases 2–3 · trap drills · Practice, 41 SQL tasks · Sandbox
One-time. No subscription.You already write SQL
Practise on numbers that look right and aren’t.
Case rounds on a practice company’s data, each with a claim the number doesn’t support. Every case you finish becomes a project for your GitHub portfolio (free account).
One claim here doesn’t hold. Tap it.
SELECT promo_code, AVG(items_total_eur)
FROM orders
WHERE status = 'paid'
AND created_at >= '2026-09-14'
AND created_at < '2026-09-21'
GROUP BY promo_code
ORDER BY 2 DESC
| promo_code | avg |
|---|---|
| AUTUMN20 | |
| NULL |
Marketing to finance: “AUTUMN20 makes baskets bigger.”
Paid orders, promo week. AUTUMN20 gives up to 20% off orders from €30.
From one case to a portfolio
Every case and episode you finish becomes a project for your GitHub portfolio (free account): the question, your SQL, the result and your decision.
- FreeCase 1: Bigger baskets?~17 min · free, no account
- Atterna FoundationsCase rounds: Cases 2–3 · trap drills · Practice, 41 SQL tasks · SandboxYou can write a query and want to defend the number it gives
- Atterna AnalystMeridian episodes 1–8 · everything in FoundationsYou already answer work questions with data
A certificate says you finished. A portfolio shows the work.
Every case and episode you finish becomes a project for your GitHub portfolio (free account): the question, your SQL, the result tables, charts and your decision. This is the sample.
Open the sample portfolioWhat’s free, and what you pay for
SQL is free: all 10 days of Start with a free account. You pay only for practice: case rounds (€19) and Meridian (€59).
Includes Foundations
Atterna Analyst
You already answer work questions with data
Meridian episodes 1–8 · everything in Foundations
€59Get Analyst
One-time. No subscription.