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Top 50 database Interview Questions

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

50questions
~13htotal time
79companies covered
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1
SQL & Data ManipulationStart here. 18 questions · ~277 min
SQL Second Highest SalaryEasy
Practice
Recently asked

Find the second distinct highest salary in S&P Global employee data without using window functions.

sql querydatabasesalaryS&P GlobalFFareportalSpectraforce Technologies
Database Normal FormsMedium
Practice
Recently asked

Explain 1NF through higher normal forms, including functional dependencies, anomalies, and normalization trade-offs.

databasenormalizationdatabase designiinMorphisAqr Capital ManagementIBM
Understanding Database SchemaEasy
Practice
Recently asked

Use PostgreSQL metadata to list the structure and column details of a database table.

database managementdatabasedatabasesPeratonCATERPILLAR
Create a Database Management SystemHard
Practice
Recently asked

Create a PostgreSQL management system and return database ownership, active membership, audit volume, and latest activity.

database managementdatabasedata managementRamp
Partitioning vs ClusteringMedium
Practice
Recently asked

Compare PostgreSQL clustering and partitioning by returning their physical behavior, query impact, and appropriate use cases.

database optimizationlarge datasetsdatabaseAltimetrik
SQL: Second Highest ValueEasy
Practice
Recently asked

Return the second highest distinct non-null value from a PostgreSQL table.

databasesqldatabase queryingItc Infotech
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2
Coding9 questions · ~138 min
Collections and MultithreadingHard
Practice
Recently asked

Implement a thread-safe collection with atomic batch updates and deterministic ordering.

multithreadingdata synchronizationCodingNiCE
In-Memory Key-Value StoreMedium
Practice

Implement SET, GET, and DELETE operations for an in-memory key-value store using a hash map.

Codingdata persistencedatabaseHHashicorpThumbtack
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3
Pipelines14 questions · ~215 min
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4
System Design4 questions · ~62 min
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5
More topics5 questions · ~77 min
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