题解 | 电商平台需要对商家的销售业绩、退款情况和客户满意度进行综合评估

select merchant_id,merchant_name,
round(sum(sale_amount)/2,2) as total_sales_amount,
round(sum(refund_amount)/4,2) as total_refund_amount,
round(avg(satisfaction_score),2) as average_satisfaction_score
from merchants_underline m
join sales_underline s
using(merchant_id)
join refunds_underline r 
using(merchant_id)
join satisfaction_underline 
using(merchant_id)
group by merchant_id,merchant_name
order by merchant_id

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