New vs Returning User Share
A hard SQL mock interview question on DataDriven, with an AI interviewer who asks follow-up questions and a hire or no-hire decision at the end.
- Domain
- SQL
- Difficulty
- hard
- Seniority
- L4
Interview Prompt
We track user activity as a raw event stream, and the growth team wants to see how each month's active users split between newcomers and people who have been around before. A user counts as new in the month of their first-ever event and returning in every month after that. For each month, give the fraction of active users who are new and the fraction who are returning.
Summary
Fresh faces versus familiar ones.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Write and run your SQL against a real database
- Answer the interviewer's follow-up questions, then get a hire or no-hire decision