Best Seller by Gross Sales

Return the seller with the highest gross sales (all rows, refunds included) and the total.

Table schema

Sellers(id INT PRIMARY KEY, name VARCHAR(10), joined DATE)
Sales(id INT PRIMARY KEY, seller_id INT, amount INT, refunded INT)

Sample data

Sellers
id | name | joined
1 | ShopA | 2025-01-01
2 | ShopB | 2025-06-01
3 | ShopC | 2026-02-01

Sales
id | seller_id | amount | refunded
1 | 1 | 100 | 0
2 | 1 | 200 | 1
3 | 2 | 150 | 0
4 | 2 | 50 | 0
5 | 2 | 70 | 1