Yesterday's Crown
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 cost dashboard shows, for each billing day, the top-spending service from the day before, where a service's spend on a day is the total of all its charges that day. Return the billing day alongside that prior-day service and its spending total.
Summary
Every dawn inherits the spending of the day before.
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