The Ground We Keep

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
L5

Interview Prompt

Return each service's footprint retention for December 2025 and January 2026: of the regions it was checked in during the month, the percentage that we check again for that same service in a later month of `svc_health`.

Summary

Every region is a claim once made. Measure how much of it endures.

How This Interview Works

  1. Read the vague prompt (just like a real interview)
  2. Ask clarifying questions to the AI interviewer
  3. Write and run your SQL against a real database
  4. Answer the interviewer's follow-up questions, then get a hire or no-hire decision