How it works

Real tables. Your query. A straight answer.

1. Pick a question. Each one comes with its input tables and the output it expects.
2. Write the query. SQLite runs by default, with MySQL-style functions like YEAR() and DATEDIFF(). Switch to real Postgres any time.
3. Run it. You'll see your output next to the expected one, and exactly which rows and cells are different.

Everything runs in your browser. Nothing to install, no sign-up; your progress stays on this device.