题解 | #某宝店铺折扣率#
某宝店铺折扣率
http://www.nowcoder.com/practice/3a56f160308441f5a79d8ac8d953e5e7
基础的sql聚合函数
select
round(
sum(st.sales_price) * 100 / sum(pt.tag_price * st.sales_num) ,
2
) discount_rate
from
sales_tb st
left join product_tb pt on pt.item_id = st.item_id