Finance wants a report with a TOTAL line at the bottom. Return country and revenue for each country with orders, sorted by revenue (highest first), followed by one final row with country = 'TOTAL' and the overall revenue.
SQLite has no ROLLUP, so combine two queries with UNION ALL, and make sure the total row sorts last.
Schema
customers(id, name, country, signup_date)
orders(id, customer_id, order_date, total)