Compute CTR, RPM, and daily RPM variability in SQL

You are given two PostgreSQL tables, campaigns and ad_events. Produce ANSI-standard SQL (runnable on PostgreSQL) that reports, per campaign, delivery and monetisation statistics for the seven-day span 2025-07-14 through 2025-07-20, both endpoints included. Any ad_events row whose dt lies outside that range must be ignored entirely. This exercise focuses on event-level click deduplication, date-window filtering, enriching rows with campaign metadata, and deriving the usual…