Does week-one API usage predict churn?

The Cloudpeak product team has a theory: customers who call the api feature in their first week become sticky, and customers who do not are far more likely to cancel. They ask you to test it on all 40 accounts.

Dataset: Cloudpeak. Every plan change writes a new subscriptions row: the old row gets an end_date and the new row starts on that same date. A row with end_date NULL is the current plan. A customer who cancels has a last row whose end_date has no follow-up row.

Task: mark each account Yes if it has at least one event with feature equal to api on a date from its signup_date up to and including 6 days later (7 calendar days in total), otherwise No. An account has churned when it has no current subscription row (no row with end_date NULL). Return used_api_week1, accounts, churned_accounts and churn_rate_pct (churned divided by accounts times 100, ROUND(x, 2)), one row for Yes and one for No, with Yes first.