Monthly Service Retention
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
- L5
Interview Prompt
For December 2025 and January 2026, find the percentage of users active in a given month who also appear in any future month. Treat missing future activity as zero retention. Return the service name, month, and retention percentage.
Summary
Users came back. Or they did not.
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