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Interview Questions

Real questions from top companies

700+ Easy450+ Medium650+ Hard
All CategoriesBehavioralSpark/Big DataSQLPython/CodingSystem Design/ArchitectureCloud/ToolsGeneral/Othereasymediumhard
1

What is the difference between OLTP and OLAP?

SQLmedium
2

Write a SQL query to find top 3 earners in each department.

SQLmedium
3

Write a query to find the top three highest-paid employees in each department using window functions.

SQLmedium
4

Write complex SQL queries involving multiple joins, subqueries, and data aggregation logic.

SQLmedium
5

Architecturally, how would you justify or challenge Hadoop vs. a cloud-native data lake (S3 + EMR/Databricks) for a greenfield enterprise data platform? Discuss scalability ceilings, cost model trade-offs, and operational complexity.

Spark/Big Datahard
6

When would you architecturally choose Dataset[T] over DataFrame in a Scala Spark pipeline, and what are the scalability and portability trade-offs? Include type-safety benefits vs. operational constraints.

Spark/Big Dataeasy
7

Convert complex SQL (CTEs, window functions, subqueries) to production-grade PySpark. Discuss when to use spark.sql() vs. DataFrame API, and the implications for testability, partitioning, and execution predictability.

Spark/Big Datamedium
8

Design a cost-aware resource strategy for a Databricks workload with spiky and batch jobs. Explain Dynamic Resource Allocation, when to disable it, and how min/max executors and spot instances affect cost and SLAs.

Spark/Big Datahard

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