题解 | 每个商品的销售总额

SELECT
    name product_name,
    total_sales,
    row_number() over (
        partition by
            category
        order by
            total_sales desc,p.product_id asc
    ) category_rank
from
    products p
    left join (
        SELECT
            product_id,
            sum(o.quantity) total_sales
        from
            orders o
        group by
            product_id
    ) a on p.product_id = a.product_id
    where total_sales is not null
order by
    category asc,total_sales desc,p.product_id asc;