Yesterday's Weather
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
A FinOps team benchmarks its cost models against the simplest possible forecast: whatever a month actually cost becomes next month's prediction. Total each month's real cloud spend and treat the prior month's total as the current month's forecast. Report each month's year-month, its actual cost, the forecast, and the percent error of that forecast.
Summary
The forecast was off. By how much?
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