Top 23
Prep plan
Updated weekly · Last refresh Aug 30

UNCOMN Data Engineer Interview Questions

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

23questions
~3htotal time
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1
PipelinesStart here. 9 questions · ~73 min
Scaling Data Pipelines EffectivelyMedium

Approach for building data pipelines that scale in throughput, reliability, and operational visibility.

InfrastructureETLUNCOMN
Batch vs Stream Processing Trade-offsMedium

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

InfrastructureStream ProcessingETLUNCOMN
Data Quality in ETL PipelinesEasy

Approach for maintaining data quality and integrity across ETL pipelines.

IdempotencyData ModelingQualityUNCOMN
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2
Coding4 questions · ~32 min
Time Complexity of Common StructuresMedium

Explain average and worst-case time complexities for arrays, hash tables, linked lists, and trees.

Hash TablesArraysTreesUNCOMN
Data Transformation Coding ChallengeMedium

Tests practical coding skills for transforming and manipulating data in a data engineering context.

Hash TablesArraysStringsUNCOMN
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3
SQL & Data Manipulation3 questions + 3 drills · ~54 min
Handling Missing and Dirty SQL DataMedium

Explain how to profile, clean, and standardize missing or dirty data before analysis.

Data WranglingCase WhenQualityUNCOMN
OLTP vs OLAP Database DesignMedium

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

financial dataperformanceData ModelingUNCOMN
SQL Query Optimization ApproachMedium

Tests structured thinking for diagnosing and improving SQL query performance.

JoinsAggregationsUNCOMN
Monthly Sales Trends by CategoryMedium
Practice
Practice drill

Aggregate monthly sales by product category and use LAG to calculate month-over-month changes.

InfrastructureToolsData WranglingTotal Wine & MoreInc.Benjamin Moore
Contact Center Agent Performance MetricsHard
Practice
Practice drill

Compute daily agent call KPIs and SLA using joins, aggregations, and window ranking in a contact center model.

ETLAggregationsData ModelingADP
Handle Missing Financial Input ValuesMedium
Practice
Practice drill

Use joins, CTEs, and CASE logic to flag and fill missing financial fields for Qlik planning records.

Data WranglingETLQualityQlik
4
Behavioral & Leadership7 questions · ~57 min
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The finish line: interview-readyComplete all 23 questions plus 3 hands-on drills to finish this plan.