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Token Churn Rate

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
mid, senior

Interview Prompt

Compute churn for API tokens in September 2026. Churn rate is the difference between tokens active on September 1 and tokens active on September 30, divided by the count on September 1. A token is active if it was issued on or before the target date and either has no expiration or expires on or after that date. Return a single churn rate.

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