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Top 50 database concepts Interview Questions

The most frequently asked database concepts questions across all roles and companies, ranked by real interview frequency. Updated daily.

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1
SQL & Data ManipulationStart here. 45 questions · ~425 min
SQL vs NoSQL DifferencesEasy
Practice
Recently asked

Query a comparison table to present the key structural and operational differences between SQL and NoSQL databases.

nosqlJoinsData WranglingCogitoRamsey SolutionsPyramid Consulting
Truncate vs DeleteMedium
Practice
Recently asked

Explain how TRUNCATE and DELETE differ in row removal, transaction behavior, and identity handling.

database managementData Manipulationdata managementCCitiusTechArcesiumDDatamatics Global Services
SQL: EXISTS vs IN With NULLMedium
Practice

Explain how EXISTS and IN behave differently when the compared value can be NULL.

null handlingJoinsdatabase conceptsGoogle
SQL: Inline Query DefinitionEasy
Practice

Use an inline query to return the average order amount by customer segment.

complex queriesdatabase queryingdatabase conceptsGoogle
Handle Hash Table CollisionsMedium
Practice

Explain what a hash table collision is and how to handle it.

database optimizationdatabase designdatabase conceptsMicrosoft
Relational vs Non-Relational DatabasesEasy
Practice

Produce a structured SQL comparison of relational and non-relational database characteristics.

nosqldatabasesdatabase conceptsAlgolia
LEFT JOIN vs INNER JOINEasy
Recently asked

Explain how INNER JOIN and LEFT JOIN differ in returned rows, NULL behavior, and performance considerations in PostgreSQL.

Joinssqldatabase conceptsAlten Delivery Centre SpainPhonepeRELX
Join Types in SQLEasy

Tests SQL join semantics and ability to choose the correct join for business questions.

Data Manipulationdatabase conceptsPayUHinduja Global SolutionsFreecharge
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2
Behavioral & Leadership3 questions · ~28 min
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3
More topics2 questions · ~19 min
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