Healthiest Service Check History
A hard 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
- 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 and run your SQL against a real database
- Answer the interviewer's follow-up questions, then get a hire or no-hire decision