sql -- 多表關聯,update(用戶獎勵)

表設計:

users_buy:

users_score:

需求:

1.根據用戶分組,找出用戶消費最高的金額

select user_name, max(paymoney) as pm
from users_buy
group by user_name;

2.更新他們的餘額

update users_score a inner join (select user_name, max(paymoney) as pm
                                 from users_buy
                                 group by user_name) b on a.user_name = b.user_name
set a.user_score=a.user_score + (b.pm * 0.1);