Three Hours for Yesterday's Numbers
A medium Spark 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
- Spark
- Difficulty
- medium
- Seniority
- L5
Interview Prompt
The nightly `daily_category_sales` job reads every date partition of `transactions`, yet the summary it rebuilds only covers sales dated on or after `2026-07-01`, so the on-call engineer has to make the read touch that slice and nothing earlier. From those sales, produce each product category's total revenue and total units sold, with the category taken from `products`.
Summary
Three terabytes scanned. One day changed.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Write and run your Spark code against the tables
- Answer the interviewer's follow-up questions, then get a hire or no-hire decision