关于MySQL多表联查并求和计算？

Question

是这样的一个情况 这里有三张表 分别是用户user，订单 trade ，和资金记录 user_money_record现在要根据用户来统计他们的订单总金额和账户余额以及充值总金额 user表id realname money1 张xx 1002 王xx 5003 李xx...

怪我咯 · Answer

I guess you may want to do this

select u.name,t.realmoney,umr.money from user u
left join 
(select uid,sum(realmoney) as realmoney from trade group by uid) t on t.uid = u.id
left join
(select uid,sum(money) as money from user_money_record group by uid) umr on umr.uid = uid

天蓬老师 · Answer

If the information in the user table is the most complete, it should look like this:

SELECT *
FROM (SELECT id, sum(money) FROM user GROUP BY id) t1 
  LEFT JOIN (SELECT id, sum(realmoney) FROM trade GROUP BY id) t2 ON t1.id = t2.id
  LEFT JOIN (SELECT id, sum(money) FROM user_money_record GROUP BY id) t3 ON t1.id = t3.id

ringa_lee · Answer

How to deal with this situation if the amount of data is too large