Data and databases practice
Every Data and databases exercise, built from a topic you can open beside it.
5 exercises runs offline
All tracks Python 139 JavaScript 184 TypeScript 76 Go 106 Rust 75 Java 81 Kotlin 66 C++ 92 C# 88 Swift 68 PHP 69 Frontend 82 Backend 139 Architecture and system design 25 DevOps and cloud 15 Data and databases 5 Data science 31 AI and LLM engineering 75 Security 26 Game development 26 Coding in the AI era 101 CS foundations 164
level
All intermediate advanced
db Quiz new A report must return every product tied at either of the two highest distinct revenue amo… Build reviewable analytical SQL with window functions, CTEs, recursive queries, and null-safe anti-joins. db Predict the output new What rows does this SQLite query print? Build reviewable analytical SQL with window functions, CTEs, recursive queries, and null-safe anti-joins. db Quiz new What does a depth limit alone guarantee in a recursive CTE over data that may contain cyc… Build reviewable analytical SQL with window functions, CTEs, recursive queries, and null-safe anti-joins. db Review AI code new Review generated tenant order query Build reviewable analytical SQL with window functions, CTEs, recursive queries, and null-safe anti-joins. db Spot the bug new Spot the bug in the top-two query Build reviewable analytical SQL with window functions, CTEs, recursive queries, and null-safe anti-joins.
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