The Conversion Story
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
- L5
Interview Prompt
From the event_data table, calculate each referral source's conversion rate from signup to paid purchase. Derive the referral source from the event's tags: classify a row as 'organic' if its tags contain "organic", else 'referral' if it contains "referral", else 'campaign_a' if it contains "campaign_a", else 'campaign_b' if it contains "campaign_b", else 'other'. For each source, the conversion rate is the number of distinct users with a purchase event divided by the number of distinct users with a signup event. Only include sources that have at least one signup. Round the rate to 4 decimal places.
Summary
Signups are one thing. Paid purchases are another. Find the gap by source.
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