Interview Mode: The Proving Ground
Three floors of timed SQL drills built to mirror real technical interviews. Start on Floor 1, graduate to the advanced questions on Floor 3, then rinse and repeat until the patterns stop surprising you.
The three floors
What the questions look like
Floor 1 targets fundamentals: SELECT with filters, aggregation, basic joins. The kind of question used as a screener before an onsite.
Floor 2 gets into windowing, top-N per group, self-joins, and the sort of aggregation gymnastics that separate strong candidates.
Floor 3 is the senior-onsite tier: gaps and islands, rolling aggregates, recursive CTEs, schema design questions. If you can finish Floor 3 under the clock, you are ready for almost any SQL screen.
How scoring works
- Each question is timed. The timer starts the moment you begin.
- Stars are awarded for correctness and speed, not for the first pass alone.
- Hints are allowed but cost stars. Use them to learn, not to grind.
- Your best performance per question counts. You can revisit any floor to improve a score.
Companion guides
Our 15 SQL interview questions guide covers the same patterns in tutorial form. Read it as a warm-up, then drill under the clock here.
Drill the Proving Ground
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