Study — Learn it, then solve it
A guided path from the basics to the hard patterns. Every lesson has live examples (real tables, real results) and a list of practice problems that use it, so you can learn a topic and immediately go apply it. Work top to bottom and you'll be ready for every question.
SQL Practice — Write & Run
Real interview problems, each with its own tables in a live in-browser SQLite database. Run Query executes your SQL and shows only your output; Submit judges it against the expected result — checked by result, so any correct approach passes. Pick a company bucket to drill one company's questions.
Theory — Concept Quiz
Multiple-choice questions on SQL fundamentals. Pick an answer to instantly see whether it's right, why, and a real-world use case. Filter by topic or difficulty.