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inn...
