Two Sides of the Ledger
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
- L5
Interview Prompt
The FinOps team reconciles each region's cloud charges against its budget allocations on a single monthly timeline, where a charge draws the region's balance down and an allocation builds it back up. Charges are stamped with a full billing date while allocations are recorded by month, so line each charge up on its month before combining the two sources. For every region and month, show the net movement and the balance standing after it, earliest month first within each region.
Summary
Two cost tables, one region. Which way does the balance tip?
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