Repeat Purchase Window
A medium 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
- medium
- Seniority
- L4
Interview Prompt
An analyst building a churn model needs the customers whose buying rhythm has slipped: the ones who once let an unusually long gap open up between one purchase and the very next, yet came back rather than going silent for good. From the transactions table, find those users and return each qualifying user ID once, smallest first.
Summary
The retention squad is looking for repeat purchasers.
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