Flexible path4 sections

Database SQL

SQL querying, data modeling, performance, and consistency.

A practical SQL interview track covering query writing, relational modeling, execution plans, indexes, transactions, locking, migrations, and production database behavior.

Recommended start

Querying

Joins, grouping, nulls, pagination, projections, and API-shaped SQL reads.

7 drillsSection 1 of 4

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Learning path

4 active sections / 39 drills

1QueryingRecommended startJoins, grouping, nulls, pagination, projections, and API-shaped SQL reads.7 drillsSection 1Open section 2Query PracticeHands-on SQL problems with concrete schemas, worked queries, edge cases, and execution reasoning.18 drillsSection 2Open section 3PerformanceExecution plans, SARGability, indexes, N plus one queries, statistics, and reporting workload tuning.7 drillsSection 3Open section 4ConsistencyTransactions, isolation, concurrency, constraints, migrations, locking, and data integrity.7 drillsSection 4Open section