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Updated weekly · Last refresh Aug 30

Alten Calsoft Labs Data Engineer Interview Questions

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

50questions
~7htotal time
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1
CodingStart here. 5 questions · ~42 min
Flatten Nested JSON to CSVHard
Practice

Flatten nested JSON objects into dot-notated CSV rows while preserving array positions and consistent columns.

json parsingData WranglingpythonAlten Calsoft Labs
Clean Code and Error HandlingEasy

Evaluates your coding practices for maintainability and robust failure behavior.

Hash TablesArraysStringsAlten Calsoft Labs
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2
Pipelines27 questions · ~227 min
Design Real-Time Operations Dashboard PipelineHard

Design a pipeline for a real-time operational dashboard, covering streaming ingestion, modeling, data quality, and dashboard serving.

InfrastructureStream ProcessingQualityAlten Calsoft Labs
Handle PySpark Data SkewMedium

Approach for detecting and mitigating skew in PySpark pipelines using partitioning, join strategies, and runtime monitoring.

Data Qualitypysparkdata skewnessAlten Calsoft Labs
Choose Delta for Lakehouse PipelinesEasy

Design a Databricks lakehouse pipeline and defend choosing Delta Lake over Iceberg and Hudi for mixed batch and streaming workloads.

Alten Calsoft Labs
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3
SQL & Data Manipulation17 questions + 3 drills · ~173 min
Star vs Snowflake for Meta AnalyticsEasy

Explain star and snowflake schemas, their tradeoffs, and when to use each in Meta-scale analytics systems.

Alten Calsoft Labs
Clustered vs Non-Clustered IndexesMedium

Explain how clustered and non-clustered indexes differ in storage, lookup behavior, and query performance.

JoinsData WranglingAlten Calsoft Labs
Understanding ACID Properties in DatabasesMedium

Explain the ACID properties of database transactions and their importance.

Alten Calsoft Labs
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
Deduplicate Out-of-Order Replication EventsMedium
Practice
Practice drill

Use ROW_NUMBER() to keep the earliest created_at 'Repl created' per entity and return out-of-order duplicates to delete.

Window FunctionsSubqueriesJoinsReplitQuantcast
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4
More topics1 question · ~8 min
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The finish line: interview-readyComplete all 50 questions plus 3 hands-on drills to finish this plan.