Healthiest Service Check History
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
- L4
Interview Prompt
We run periodic health checks across a fleet of services, and each check logs an uptime score. Find whichever service reached the highest uptime score ever recorded, then take that service's whole check history and for each of its checks show the check time, the time of that service's previous check, and the day gap between the two.
Summary
The healthiest service. Full history.
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