You are given a table of customer activity from PNC digital marketing campaigns. Write a SQL query to identify the top-performing customer cohorts, where a cohort is defined by cohort_month. Return each cohort's total revenue and customer count, sorted from highest total revenue to lowest, and show only the top 3 cohorts.
Because this is an easy SQL exercise, solve it using only a single table with aggregation, sorting, and limiting.
| Column | Type | Description |
|---|---|---|
| activity_idPK | INT | Unique activity row identifier |
| customer_id | INT | Customer identifier |
| cohort_month | VARCHAR(7) | Customer acquisition cohort in YYYY-MM format |
| channel | VARCHAR(30) | Marketing acquisition channel |
| revenue | DECIMAL(10,2) | Revenue attributed to the activity |
| activity_date | DATE | Date of customer activity |