Interactive SQL Lab • Automated Grading Suite • 20 Guided Challenges
SQL Practice Challenges & Exercises
Test your real-world SQL skills with interactive problem prompts and instant automated test validation against live in-memory DuckDB datasets.
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Basics Easy
1. Top 5 Highest Paid Employees
The executive board needs to review compensation for the highest-paid team members across all departments.
Find the top 5 highest earning employees in the company.
Target Tables & Columns:
employees
Expected columns:
first_name, last_name, job_title, salary Press Ctrl + Enter to run test
Test Suite Validation Results
Ready for Evaluation
Write your SQL solution query above and click "Run & Test Solution".
Mastering SQL Queries Through Interactive Practice
Reading SQL documentation is only the first step. True SQL fluency requires writing actual queries, joining messy relational tables, debugging data type mismatches, and calculating complex aggregations. Our interactive SQL exercises provide an authentic environment with automated feedback on your solutions.
Structured Learning Progression
1. Fundamentals & Filtering
SELECT statements, column aliasing, WHERE conditions, pattern matching with LIKE, and logical operators.2. Aggregations & Grouping
COUNT, SUM, AVG, MIN, MAX functions, GROUP BY expressions, and filtering aggregate buckets with HAVING.3. Relational Multi-Table JOINs
Connecting primary and foreign keys using INNER JOIN, LEFT JOIN, and 3-way table joins.4. Analytical Window Functions
DENSE_RANK(), ROW_NUMBER(), PARTITION BY clauses, CTEs (WITH), and running cumulative totals.Frequently Asked Questions
Each challenge gives you a realistic business scenario and problem prompt. You write your SQL query in the interactive editor and click "Run & Test Solution". Our test runner executes your query against an in-browser DuckDB-WASM relational database and validates your result against verified solutions in real time.
No setup or installation required! The entire database engine runs 100% inside your browser via WebAssembly, pre-seeded with rich mock relational datasets generated by Faker.js.
Yes. Your completed challenges and progress percentage are saved automatically in your browser localStorage, allowing you to return and resume anytime.
Our challenges cover everything from fundamental SELECT statements, WHERE filtering, pattern matching, GROUP BY aggregations, and HAVING clauses to multi-table INNER/LEFT JOINs, CASE WHEN classifications, and advanced analytical Window Functions (DENSE_RANK, ROW_NUMBER, running totals).