The Conversion Story
A medium SQL 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
- SQL
- Difficulty
- medium
- Seniority
- L5
Interview Prompt
Our referral-source conversion numbers don't reconcile, so we're rebuilding them from `event_data`, labelling each signup or purchase event by which of "organic", "referral", "campaign_a" or "campaign_b" its raw `tags` text carries. For every `referral_source`, report `signup_users`, `purchase_users` and `funnel_users` (unique users who signed up, purchased, or did either) plus `conversion_rate`, purchasers over signups.
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 and run your SQL against a real database
- Answer the interviewer's follow-up questions, then get a hire or no-hire decision