SQL Quiz
Test what you know about SQL. Pick a difficulty, answer ten questions, and get an explanation with every result.
Choose a difficulty to start.
About this SQL quiz
This quiz is a quick way to check how well you know SQL, the language used to read and manage data in relational databases like PostgreSQL, MySQL and SQL Server. Each round pulls ten random questions from the difficulty you pick, so you can play it more than once without seeing the exact same set every time.
How the difficulty levels work
Easy questions cover the fundamentals: SELECT statements, filtering with WHERE, sorting, and basic functions like COUNT. Medium questions move into joins, GROUP BY and HAVING, subqueries, and constraints. Hard questions test more advanced ideas such as window functions, common table expressions, normal forms, isolation levels and query execution order — the kind of thing that comes up in technical interviews and real production work.
Who it's for
Useful for students learning SQL for the first time, developers brushing up before an interview, and anyone who works with data and wants a fast, free way to test their SQL knowledge online. Every answer comes with a short explanation, so it works as a lightweight study tool as well as a quiz.
Everything runs in your browser — no sign-up, no data sent anywhere, and no limit on how many times you can retake it.