Write a query to calculate the monthly retention rate of users acquired through a specific paid social campaign at Affirm.
Use the campaign named Affirm Paid Social - Summer 2025. Treat any user activity during a calendar month as retention for that month. Include users with valid acquisition dates and report months from acquisition through the latest observed activity month.
Output
- One row per acquisition cohort month and activity month, with
cohort_month, activity_month, month_number, retained_users, cohort_users, and retention_rate.
- Include zero-activity months through the latest observed activity month, order by
cohort_month, then activity_month.
