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Handling Many-to-Many Join Duplicates

MediumSQL & Data Manipulation00:00
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Your question is Handling Many-to-Many Join Duplicates. Take a moment with it on the right.

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Problem

You are asked to explain how to handle duplicate records created by a many-to-many join in SQL. Focus on why row multiplication happens, how it affects aggregates, and how you would structure a safer query for reporting datasets used in JPMorganChase dashboard surfaces.

What This Tests

  • Understanding of join cardinality
  • Ability to prevent double counting in aggregates
  • Use of CTEs or pre-aggregation to control grain
  • Judgment on when DISTINCT is and is not appropriate