The Subscription Ghost
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
- L5
Interview Prompt
A billing-integrity team is chasing accidental recurring charges: a customer billed the same amount for the same product about a month after the last time, usually a duplicate subscription or a botched retry. Within each user and product pairing, compare every charge to the one immediately before it in time, and surface the charges that repeat the previous amount exactly and land 35 days or fewer after it.
Summary
Some charges come back to haunt the same card a month later.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Write your sql solution with real code execution
- Get instant feedback and a hire/no-hire decision