SQL · Meta · Hard
This round is about time-based event attribution, aggregating business metrics (impression counts, conversion rates, spend and revenue), handling timestamps, and matching events at the user/ad level — a practical exercise rather than a theoretical one. You are given two tables from an advertising system. ad_impressions records every ad that was served: Column Type Meaning impression_id STRING Primary key; identifies one served impression. user_id STRING The viewer who saw…
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