Top 50 ETL Interview Questions

Prepare valid encounter records by trimming text, excluding missing values, and removing invalid charges.

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Demonstrate ETL by extracting staged sales, cleaning values, validating records, and producing load-ready output.

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Clean staged customer events and return valid records with invalid-row reasons using joins and CASE logic.

data cleaningJoinsETLSnowflake Computing

Clean and summarize dirty order data by customer, excluding invalid rows and flagging duplicates.

data cleaningData ManipulationETLSnowflake

Upsert the newest staging records into a PostgreSQL dimension while preserving newer target data.

Data ManipulationETLdata migrationSnowflake

Count unique respondents by Python or R library and return the most commonly used libraries first.

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