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SELECT u.first_name || ' ' || u.last_name AS full_name,
       COUNT(o.id) AS order_count,
       ROUND(SUM(o.total), 2) AS lifetime_value
FROM users u
LEFT JOIN orders o ON o.user_id = u.id
GROUP BY u.id
ORDER BY lifetime_value DESC
LIMIT 20;

Real SQL Engine

Powered by SQLite compiled to WebAssembly. Your queries run against a real database, not a fake simulator.

8 Realistic Tables

1,370+ rows of realistic data across users, orders, products, employees, payments, reviews and more.

Guided Challenges

12 hand-crafted challenges from easy SELECT queries to advanced CTEs and RFM segmentation.

Monaco Editor

The same editor as VS Code — syntax highlighting, autocomplete, keyboard shortcuts and formatting.

Instant Results

See query results in milliseconds. Typed cells for numbers, dates and NULLs. Export-ready layout.

Sandboxed & Safe

Only SELECT queries allowed. Every execution runs in an isolated in-memory database. Zero risk.

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