sql left join的多表应用

SELECT a.user1 用户,m1 总充值,m2 除设备自带金额充值, IFNULL(m3,0) 消费,m1-IFNULL(m3,0) 余额 FROM
(SELECT  SUM(rbd.`TRADEMONEY`+rbd.GIFTMONEY) AS m1,rbd.OPERATORID AS user1 FROM rb_balance_details rbd
WHERE rbd.`TYPE`  IN(0,1,3,4,9,10,11,12) AND rbd.TRADETIME<'2015-07-01 00:00:00' GROUP BY rbd.OPERATORID) a
LEFT JOIN
(SELECT  SUM(rbd.`TRADEMONEY`+rbd.GIFTMONEY) AS m2,rbd.OPERATORID AS user2 FROM rb_balance_details rbd
WHERE rbd.`TYPE`  IN(0,1,3,4,9,10,12) AND rbd.TRADETIME<'2015-07-01 00:00:00' GROUP BY rbd.OPERATORID)b ON a.user1=b.user2
LEFT JOIN
(SELECT  SUM(rbd.`TRADEMONEY`) AS m3,rbd.OPERATORID AS user3 FROM rb_balance_details rbd
WHERE rbd.`TYPE`  IN(2,6,8,13) AND rbd.TRADETIME<'2015-07-01 00:00:00' GROUP BY rbd.OPERATORID)c ON a.user1=c.user3