SQL & Database interview practice

Query reasoning, indexing strategy, transactions, and schema design — live verbal SQL interviews without a whiteboard.

Topics this interview probes

Query execution plans Indexing strategy Transactions & isolation Schema design Window functions Query optimization

A report query got 100x slower after a data migration. Walk me through reading the execution plan.
Explain when a composite index stops helping, and how you’d verify the fix.
Pick an isolation level for a booking system and defend the anomalies you accept.

The live interviewer generates fresh, role-tailored questions — and drills down when your answers are vague.