No. SQLab Hub is 100% free: every lesson, challenge, project and test, and the Playground. There is no paid plan and nothing to buy. If you bought the ebook or a Premium subscription when they were on sale and need help with it, email support@sqlabhub.com with the Razorpay payment ID.

How do I delete my account and data?

Email support@sqlabhub.com from the address on the account and ask for deletion. It is carried out within 30 days. The Privacy Policy lists what is stored.

Can I use SQLab Hub in a class?

Yes. Reading lessons and running queries needs no account, so students can start straight away. Each student who wants saved progress needs their own free account.

My query works elsewhere but fails here.

The Playground runs SQLite and accepts read-only queries (SELECT and WITH). Functions that exist only in MySQL, PostgreSQL or SQL Server will not run, and CROSS JOIN and recursive CTEs are blocked to protect the shared server.

I found a mistake in a lesson.

Please report it with the page address. Confirmed errors are corrected on the page.