The Weight of Every Purchase
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
The finance analytics group at our marketplace wants to understand how each shopper's lifetime spend accumulates over time, so they can spot the exact purchase where a customer crosses a high-value threshold and flag them for loyalty outreach. For every purchase a customer has made, they want to see the customer, the date that purchase happened, and how much that customer had spent in total up to and including that purchase, with the timeline read in the order the purchases actually occurred. Walk through one customer's history and the picture is a steadily climbing balance; do this for everyone at once.
Summary
Each order carries everything that came before it. Show the load building, customer by customer.
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