3716. Find Churn Risk Customers

Table: subscription_events +------------------+---------+ | Column Name | Type | +------------------+---------+ | event_id | int | | user_id | int | | event_date | date | | event_type | varchar | | plan_name | varchar | | monthly_amount | decimal | +------------------+---------+ event_id is the unique identifier for this table. event_type can be start, upgrade, downgrade, or cancel. plan_name can