About SQLTest.online
A free online SQL trainer: practice tasks, lessons and a playground on real databases.
SQLTest.online helps you learn SQL from scratch, keep your skills sharp for work and prepare for technical interviews. You write real queries in the browser, run them against real database engines and get instant feedback from automatic tests.
What You Can Do Here
All tools work with the same databases, so you can read a lesson, try the query in the playground and then solve tasks on the topic.
Practice tasks
Tasks grouped by topic, difficulty and database. Automatic tests compare your result with the expected one.
SQL lessons
A course from SELECT and WHERE to joins, window functions, transactions and query optimization.
SQL playground
An online SQL editor for MySQL, MariaDB, PostgreSQL, SQL Server, Oracle, SQLite and Firebird.
SQL skills test
12 practical tasks of different difficulty and three hours to solve them. The result shows your level.
Interview simulator
Questions for the position and level you choose, with feedback on every answer, like a real technical interview.
SQL books
Books on SQL and databases that we recommend for further study.
How We Build the Tasks
The tasks are written and reviewed by people who work with data every day: SQL trainers, data analysts and backend developers.
Real-world scenarios
Tasks come from analytics, reporting and application development: sales, rentals, flights, employees.
Checked on real engines
Every query runs on a real database server, not on an emulator, so you learn the dialect you'll meet at work.
From basics to advanced
Task sets start with simple queries and go up to joins, subqueries, window functions and performance.
Continuous review
We read user feedback and update tasks, expected answers and explanations to keep them accurate.
Who It's For
Students
Learn SQL for your course or on your own, with lessons and tasks that build on each other.
Developers
Refresh your SQL, learn the differences between databases and prepare for technical interviews.
Data analysts
Practice aggregation, window functions and analytical queries on realistic data.
An Open Project
The source code of SQLTest.online is open on GitHub. The site has no paid plans for lessons and tasks: it runs on donations from its users. Join the community to ask questions, report a mistake in a task or suggest a new one.
Thanks to Our Contributors
- Artem Latyshev
- Alexander Gureev
- Georgy Grigorchuk
- Elena Selsky
- Vladimir Revyakin
Frequently Asked Questions
What is SQLTest.online and who builds it?
SQLTest.online is an interactive platform for learning and practicing SQL. It is built by people with practical experience in SQL training, backend development and data analysis, and its source code is open on GitHub.
How can I practice SQL online with real database engines?
Choose a task and write your query in the browser editor. It runs on a real database server: MySQL, MariaDB, PostgreSQL, SQL Server, SQLite, Firebird or DuckDB, depending on the task.
How many SQL exercises are there?
The question bank holds 486 practice tasks organized by topic and difficulty, from basic queries to analytical problems.
Can SQLTest.online help with SQL interview preparation?
Yes. Tasks cover joins, aggregation, subqueries, window functions and other topics common in technical interviews, and the interview simulator lets you rehearse the interview itself.
Is SQLTest.online free?
Yes. Practice tasks, lessons, the SQL playground and the SQL skills test are free. The project is supported by donations.