题解 | 每个商品的销售总额

select p.name as product_name, sum(quantity)as total_sales,
row_number() over( 
    partition by p.category order by sum(quantity) desc
) as category_rank
from
products as p inner join
orders as o
on p.product_id = o.product_id
group by o.product_id

本来像加order by的，但是加了反而报错，不加反而对了，有点莫名其妙。还有就是其实我觉得inner join的逻辑可能更符合业务逻辑？因为我们要统计的是同时在商品栏目和用户购买的数据。