Learn SQL: SQL Case Files

Open the case file. The evidence is in the database.

Learn SQL for free through 100 authored leads and 10 complete investigations. Read the brief, inspect the schema, write a real query, and use the returned rows to prove what happened.

Each lead gives you a question and a working dataset. Run your SQL, study the result, revise your approach, then verify the finding when the evidence fits. Every investigation is authored, so the clues, datasets, and conclusions belong to a complete case.

WORK 100 AUTHORED LEADS
Ten investigations take you from the foundations to advanced analysis:
• SELECT, WHERE, ORDER BY, and LIMIT
• COUNT, SUM, AVG, GROUP BY, and HAVING
• INNER JOIN and LEFT JOIN
• Subqueries and CASE expressions
• Window functions and common table expressions

BUILD PRACTICAL SQL JUDGEMENT
• Turn a case objective into a query
• Explore tables and relationships through the schema
• Read returned rows instead of guessing from syntax
• Use clear feedback to correct a failed investigation
• Reopen filed leads and improve your solution

START WHERE YOUR SKILLS FIT
New to SQL? Begin with Case 001 and learn the query desk step by step. Already comfortable with the basics? Choose a later investigation and meet a harder set of evidence.

Archie, your SQL Case Guide, can offer a focused hint when you are stuck. Academy field guides explain the underlying concepts, while the Skill Map shows how each investigation builds your SQL toolkit.

THE CURRICULUM STAYS FREE
All 100 authored leads and the complete SQL learning route are free. There is no subscription. Start without an account, and keep your learning progress and settings on your device. Analytics can be disabled in Settings.

Query verification, Archie guidance, verification links, and purchase restoration require an internet connection.

An optional one-time Supporter purchase helps fund future investigations. It never limits the curriculum.

Your first case is waiting.