Transaction Timeline
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
- L3
Interview Prompt
Our lifetime-value model is being fed a purchase snapshot with a row per transaction, so every buyer shows up a dozen times instead of once. Rebuild it from the users and transactions tables: one row per customer who has bought something, with their username, earliest and latest purchase date, and total spend.
Summary
First purchase to last. The full spending arc.
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