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Peak Concurrent Tokens

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

Domain
SQL
Difficulty
hard
Seniority
senior, staff

Interview Prompt

For every API token that has ever been issued, find the greatest number of concurrently active tokens during its lifetime and the first date that peak was reached. A token is active from its issued date until the day before its expiration; tokens with no expiration are considered still active. Return the token ID, peak concurrent count, and peak date.

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