题解 | 三表连接
三表连接
https://www.nowcoder.com/practice/c86c980ce4544959b4691448c937620e
select
c.商品类型,
sum(a.支付金额) as 支付金额,
sum(b.总运费) as 总运费,
sum(b.总运费) / sum(a.支付金额) as 运费占比
from
订单表 a
left join
运费表 b on a.订单号 = b.订单号
left join
品类表 c on a.商品号 = c.商品号 and b.商品号 = c.商品号
where
c.商品类型 is not null
group by
1
