题解 | 每个商品的销售总额

with t as (select o.product_id, o.quantity, p.name, p.category
from orders o
inner join products p 
on o.product_id = p.product_id), 

t2 as (select name as product_name, sum(quantity) as total_sales
from t
group by product_name),

t3 as (select * from t2 
left join products p on t2.product_name = p.name)

select product_name, total_sales, 
row_number() over (partition by category order by total_sales desc) as category_rank
from t3