Ride the SQL curve
from basics to mastery.

Learn SQL online with interactive lessons and real datasets — free, with no signup. From SELECT and JOINs to window functions, CTEs, and interview-ready practice in your browser.

Start Learning Practice Now

top_trails.sqlready

-- busiest trails by annual footfall
SELECT id, trail, park, footfall
FROM   trails
JOIN   visits USING(trail_id)
ORDER BY footfall DESC LIMIT 3;

Run· 3 rows · 12ms✓ passed

idtrailparkfootfall

TR042Bright AngelGrand Canyon184,500

TR017Half DomeYosemite42,850

TR088Cadillac SummitAcadia36,120

Jump to a topicSELECT WHERE JOIN GROUP BY CTE Window Functions

Learning Tracks

⚡

Beginner

SQL Basics

Start here. Learn to query data, filter results, sort output, and manage your own tables.

12 topics →

🎯

Beginner

Filtering & Conditions

Refine your queries with powerful filtering and conditional logic.

5 topics →

📐

Intermediate

Aggregation

Summarize data with counts, sums, averages, and grouping.

7 topics →

🔀

Intermediate

Joins & Subqueries

Combine data from multiple tables and write nested queries.

8 topics →

🧠

Advanced

Advanced SQL

CTEs, window functions, ranking, and row-level analytics.