Repeat Buyers Across Halves
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
The retention team is reviewing 2026 to find shoppers who stayed engaged the whole year instead of for just one season. Surface the users who bought something in both the first half of the year, January through June, and the second half, July through December, listed by user ID.
Summary
First half buyer. Second half buyer. Same person.
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