SQL Playground

Practice 64 SQL exercises with instant feedback on a real PostgreSQL 17 database running in your browser. No signup, no server, nothing leaves your tab.

What you can practise

• 64 exercises on the Northwind dataset, grouped by topic.
• Filtering, joins, aggregation, subqueries, window functions, CTEs, set operations, and date/string functions.
• Instant row-level comparison with the reference answer.
• A real PostgreSQL 17 database compiled to WebAssembly, running entirely in the browser.

Read the SQL deep dive or open the practice sheet.