Learn SQL by solving cases, not memorizing syntax.
Read the problem. Write the query. Get instant feedback. Use hints when you're stuck — and learn how an expert thinks through the solution.
You'll be writing real SQL — not choosing answers.
Read the case. Write the query. Run it. Get instant feedback.
Finding Nina
| id | name | country |
|---|---|---|
| 1 | Sam | Germany |
| 2 | Nina | Canada |
| 3 | David | Brazil |
| 4 | Maya | Japan |
| 5 | Daniel | Australia |
| … 1 more row | ||
| id | name | country |
|---|---|---|
| 2 | Nina | Canada |
Pick your starting point
50 cases. Three difficulty levels. Start where your SQL stands today.
How each case works
Alex, ByteMart's data analyst, gets a question from the manager. You get the same question, the same data, and the same challenge: write the SQL that answers it.
Read the case
Alex gets a question from the manager. You get the same question and the same data.
Write your SQL
Think through the problem, then write the query in a real SQL editor.
Run it — instant feedback
Your query runs against real data. You know immediately if it's right.
Stuck? Ask for a hint
Hints walk through Alex's own reasoning, without handing you the answer.
Compare with Alex's solution
See the final query and what it returns, then move to the next case.
What you'll practice
Build SQL skills that actually transfer to real analysis.
Filtering
WHERE · AND / OR · BETWEEN
Aggregation
GROUP BY · HAVING · SUM · COUNT
Joins
INNER JOIN · LEFT JOIN · multi-table queries
CTEs & Subqueries
Break complex problems into steps
Window Functions
Ranking · running totals · comparisons
Date Analysis
Trends · periods · time-based analysis
Conditional Logic
CASE WHEN · business rules
Advanced Analysis
RFM · cohorts · recursive CTEs
Pick a case. Solve a problem.
Real questions. Real data. Your SQL.
Built for people who want to get better at SQL.
Beginners
Build confidence by solving your first real SQL problems.
Data Analysts
Practice the type of questions you'll encounter in real analysis.
Interview Prep
Practice thinking through SQL problems instead of memorizing answers.
Experienced SQL Users
Sharpen your SQL with increasingly difficult cases.
Frequently asked questions
What is SQLCase?
SQLCase is a free SQL practice platform where you solve realistic data problems by writing SQL queries.
Is SQLCase free?
Yes. All 50 cases are free to solve.
Do I need SQL experience to start?
No. Cases progress from beginner to advanced, so you can start at the level that matches your experience.
What SQL topics are covered?
Cases cover filtering, aggregation, JOINs, CTEs, subqueries, window functions, date analysis, conditional logic, cohorts, RFM, and more.
How does SQL grading work?
Write your query in the editor, run it, and receive immediate feedback on whether your result solves the case.
What happens if I get stuck?
Use hints to get guidance without immediately revealing the solution. When you're ready, compare your approach with Alex's solution.