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Cross-Variant User Pairs

A medium SQL mock interview question on DataDriven. Practice with AI-powered feedback, real code execution, and a hire/no-hire decision.

Domain
SQL
Difficulty
medium
Seniority
L4

Interview Prompt

The experimentation team is looking for cross-variant contamination. Pair users who participated in the same experiment under different variants but on the same platform. Show both user IDs for each qualifying pair.

Summary

Same experiment. Different variants. Who overlaps?

How This Interview Works

  1. Read the vague prompt (just like a real interview)
  2. Ask clarifying questions to the AI interviewer
  3. Write your sql solution with real code execution
  4. Get instant feedback and a hire/no-hire decision

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