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By topic
Drill one pattern at a time. Window functions, JOINs, GROUP BY, subqueries, CTEs, NULL handling, CASE WHEN.
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FAANG plus marketplaces and finance. Each exercise tagged from real interview reports.
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Real public datasets, not synthetic ecommerce. The schemas your future job actually uses.
Every exercise on SQL Quest has the same anatomy: prompt, sample data, expected output, your editor, instant feedback. Here's a Medium-difficulty Window Function exercise.
📋 The prompt
For each department, find the top 3 highest-paid employees. If two employees are tied at the same salary, both should appear (and they share the rank). Output columns: name, department, salary, ordered by department, then salary descending.
📊 Sample data — employees
| id | name | department | salary |
|---|---|---|---|
| 1 | Alice | Engineering | 180000 |
| 2 | Bob | Engineering | 170000 |
| 3 | Carol | Engineering | 170000 |
| 4 | Dan | Sales | 120000 |
| 5 | Eve | Sales | 110000 |
✅ Expected output
| name | department | salary |
|---|---|---|
| Alice | Engineering | 180000 |
| Bob | Engineering | 170000 |
| Carol | Engineering | 170000 |
| Dan | Sales | 120000 |
| Eve | Sales | 110000 |
💡 Hint progression
Hint 1: "Ranking ties — which window function keeps both Bob and Carol at rank 2 instead of giving one rank 3?"
Hint 2: "Wrap your ranked query in a CTE. You can't filter on a window function in the same WHERE."
Show Structure: skeleton with WITH/PARTITION/ORDER BY blanks.
🔓 Solution (revealed only when you ask)
SQL Quest tracks your proficiency across 10 canonical skills. Each exercise contributes points to the skills it exercises — weighted by difficulty, your speed, and how many hints you used.
More points
First-attempt solve on a Hard exercise without revealing structure or asking the AI Coach. The clearest signal of real mastery.
Some points
Used Show Structure or asked the Coach. Still counts — you learned something — but at a discount. The radar reflects guided solves differently than cold ones.
Mastery check
After a lesson, the Coach drops you on 2-3 unseen exercises in the same skill. Recognition isn't enough; you have to produce. That's what gates advancement.
Free, browser-only, no signup. The Coach can pick the next exercise — or you can browse.
Open SQL Quest — Free ⚡