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Healthiest Service Check History

A hard SQL interview practice problem on DataDriven. Write and execute real sql code with instant grading.

Domain
SQL
Difficulty
hard
Seniority
mid, senior

Problem

Find the service(s) with the highest-ever uptime score, then for those services show each check date, the previous check date, and the gap in days between them. Results should be ordered by check date, most recent first.

Practice This Problem

Solve this SQL problem with real code execution. DataDriven runs your SQL queries against a live PostgreSQL database and grades it instantly.