The Company You Keep
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
We run an ad platform and want to know how much any two users overlap in the campaigns they were shown. For each pair of users that shares at least one campaign, report the overlap ratio: the number of campaigns both saw, divided by the number of campaigns at least one of them saw, rounded to two decimals.
Summary
Two viewers, one audience: measure how far their campaign worlds overlap.
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