PGExercises
pgexercises.com
A free PostgreSQL practice site with 80+ exercises covering joins, aggregation, subqueries, window functions, recursive queries, and date operations — running against a realistic club membership dataset.
Why it is useful
Focuses specifically on PostgreSQL rather than generic SQL, covering features like CTEs, window functions, and the LATERAL join that most SQL tutorials skip. The exercises use a realistic schema (a sports club with members, facilities, and bookings) rather than toy tables, which makes the problems feel like real work. The solution explanations are detailed enough to teach the reasoning, not just the answer.