The Ones Who Return
A medium SQL mock interview question on DataDriven. Practice with AI-powered feedback, real code execution, and a hire/no-hire decision.
- Domain
- SQL
- Difficulty
- medium
- Seniority
- mid
Interview Prompt
Our member growth team suspects that a large share of the people who buy from us try the service exactly once and never come back, while a smaller core keeps returning again and again, and before the quarterly retention review they want one anchor number to ground that story. Using the complete purchase history, work out what share of the entire member base counts as repeat buyers, meaning any member who shows up with more than a single purchase to their name, and express that share as a percentage of all members rounded to two decimal places.
Summary
One purchase is a trial. Two is a habit. Find how many members formed one.
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