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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
- L4
Interview Prompt
Data science wants to model spending trends per user over time. For every row in transactions, pull that user's previous transaction amount (by transaction_date) onto the same row, leaving the value empty on a user's first transaction. Return the user_id, total_amount, transaction_date, and the previous amount.
Summary
What did they spend last time? Context changes everything.
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