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SQL Casebook

Learn SQL by solving cases. Each casebook is a story with its own database, from a first SELECT to joins, subqueries, triggers and transactions.

Open a casebook

Casebooks

A Sherlock Holmes casebookThe Baker Street IndexNine cases from the original stories, rebuilt as a database. Query, fix and safeguard the index, from a first SELECT to triggers and transactions.9 chapters · 50 SQL cases · 44 quiz questions

How it works

Graded against real results

Every SQL case runs on a fresh copy of the casebook's database. When you submit, the page runs a reference answer on the same data and compares the two results, so any correct query passes, not only the one it expects. Cases that change data are checked by inspecting the database afterwards and by testing the constraints or triggers you created.

Quiz questions cover the theory SQLite cannot run, such as ER modelling, normal forms, isolation levels and access control. The reference answers ship with the page, so this is for practice, not assessment.

The same SQLite engine runs the SQLite workspace, so once a case makes sense you can try the same queries on a database of your own.