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Updated weekly · Last refresh Aug 30

Persistent Systems Data Engineer Interview Questions

The questions to prepare for a Persistent Systems Data Engineer interview. Questions from real interview reports rank first. Updated weekly.

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1
SQL & Data ManipulationStart here. 5 questions + 2 drills · ~64 min
Second Highest Without AggregatesHard
Practice
Recently asked

Find the second highest salary in each department without using aggregate functions.

SubqueriesRankingSelf-JoinsPersistent Systems
OLTP vs OLAP Database DesignMedium
Recently asked

Explain OLTP vs OLAP designs, including schema shape, workload patterns, and when each is appropriate in a data platform.

financial dataperformanceData ModelingPersistent Systems
Optimize Slow SQL QueriesMedium

Tests query tuning skills, including indexing, execution plans, and rewriting strategies.

SubqueriesJoinsAggregationsPersistent Systems
Compare Two Tables in SQLMedium
Practice
Practice drill

Compare Persistent QA pipeline records across tables and report missing or mismatched test data using a full outer join.

JoinsData WranglingAggregationsPersistent Systems
Second-Highest Salary Without LIMITEasy
Practice
Practice drill

Use nested aggregation subqueries to find the second-highest distinct salary without LIMIT.

Subqueriessql queryPersistentPersistent Systems
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2
Coding5 questions · ~44 min
Merge Two Sorted Linked ListsEasy
Practice

Merge two sorted singly linked lists into one sorted list by relinking existing nodes.

RecursionLinked ListsSortingPersistent Systems
Online Assessment Topic CoverageMedium

Evaluates your readiness across core CS fundamentals and common assessment topics.

Hash TablesArraysStringsPersistent Systems
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3
Pipelines23 questions · ~200 min
Cleaning Missing Values in PipelinesEasy
Recently asked

Approach for handling missing values in a pipeline with data quality checks and repeatable transformations.

Data WranglingETLQualityPersistent Systems
Real-Time Dashboard Pipeline DesignHard
Recently asked

Approach for building near-real-time dashboard pipelines with streaming, orchestration, and data quality controls.

Stream ProcessingSchedulingDependenciesPersistent Systems
Batch vs Stream Processing Trade-offsMedium
Recently asked

Compare batch and stream processing across latency, complexity, cost, and data quality in a modern analytics pipeline.

InfrastructureStream ProcessingETLPersistent Systems
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4
Behavioral & Leadership8 questions · ~70 min
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The finish line: interview-readyComplete all 41 questions plus 2 hands-on drills to finish this plan.