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What challenges arise with duplicate records, and how do you address them?

SQLmedium0.6 min readPremium
Frequency
Low
Asked at 1 company
Category
487
questions in SQL
Difficulty Split
130E|271M|86H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
EPAM
Key Concepts Tested
joinpartition
Expert AnswerPremium
118 wordsInterview-ready
Duplicate record challenges: Inconsistent analytics, incorrect aggregates, join explosions, compliance issues. Solutions: (1) Deduplication—use ROW_NUMBER() or DISTINCT with clear criteria; choose one row per key (e.g., latest by timestamp). (2) Prevention—unique constraints, idempotent pipelines, MERGE with conflict resolution. (3) Detection—dbt unique tests, row-count checks, checksum validation. (4) Golden record—MDM or survivorship rules for conflicting sources....
The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations. It covers performance optimization strategies, common pitfalls to avoid, and real-world examples from companies like EPAM. The answer also includes follow-up discussion points that interviewers commonly explore.

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