The Subscription Ghost
A medium SQL mock interview question on DataDriven, with an AI interviewer who asks follow-up questions and a hire or no-hire decision at the end.
- 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 so the team can clear that backlog.
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 and run your SQL against a real database
- Answer the interviewer's follow-up questions, then get a hire or no-hire decision