题解 | #某宝店铺折扣率#

# 统计折扣率（GMV/吊牌金额，GMV指的是成交金额）
select round(sum(sales_price)/sum(tag_price*sales_num)*100,2) as discount_rate
from sales_tb
left join product_tb on sales_tb.item_id=product_tb.item_id

错误代码

select sum(sales_price/sales_num)/sum(tag_price)*100 AS 'discount_rate(%)'
from sales_tb
left join product_tb on sales_tb.item_id=product_tb.item_id