A complete SQL interview prep portal, organised from basics to advanced. Every answer comes with a diagram and runnable SQL so you can explain the idea and show the code.
Basic SQL Interview Questions
The fundamentals every SQL interview starts with: SELECT, WHERE, JOINs, keys, GROUP BY, NULL handling and the core clauses.
BeginnerIntermediate SQL Interview Questions
Subqueries, aggregate vs window functions, HAVING vs WHERE, set operators, CTEs and the differences interviewers love to probe.
IntermediateAdvanced SQL Interview Questions
Window function depth, recursive CTEs, isolation levels, execution plans, pivoting and the questions that separate seniors.
AdvancedScenario-Based SQL Questions
Write-the-query challenges: find duplicates, second highest salary, running totals, gaps and islands, top N per group.
AppliedDatabase Design Interview Questions
Modeling relationships, choosing keys and data types, ER diagrams, one-to-many vs many-to-many, and schema trade-offs.
DesignSQL Performance Interview Questions
Indexing strategy, index seek vs scan, reading execution plans, why a query is slow, sargable predicates and tuning.
AdvancedStored Procedure Interview Questions
Procedures vs functions, parameters and output, error handling with TRY CATCH, transactions, and when to use each.
IntermediateNormalization Interview Questions
The normal forms explained: 1NF, 2NF, 3NF and BCNF, functional dependencies, anomalies, and when to denormalize.
DesignPreparing for a SQL interview?
Work through the categories above, sharpen your query writing with the hands-on SQL exercises, then go deeper with the SQL interview guide and the SQL functions library. For focused help, book a session with a mentor.