Code Room
Vibe codingHardvc-g049
Subject Ai verificationLevel Senior–Staff~18 minCommon in Databases & SQL · Code quality & review interviewsIndustries Software development, Technology

Question

An agent wrote a 40-line analytics SQL query to compute monthly active users with retention cohorts across three joined tables. It returns plausible-looking numbers and runs fast. The query uses LEFT JOINs, a window function, and a DATE_TRUNC you didn't scrutinize. The output will drive a board metric. How do you verify the numbers are right before they leave your hands — given you don't fully follow the query?

What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it — tests, edge cases, reading critically — and how you’d re-prompt or decompose to get it right.

Describe your solution

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.