Mysql 加入和求和

Question

请看这张图

http://i.stack.imgur.com/A2RB2.jpg

我想得到

1. 桌子上的钱来了
2. 请假总金额
3. 使用 id 内部连接 ​​emp

这是我的问题

SELECT uid,SUM(money) FROM come 
INNER JOIN emp ON(come.uid = emp.id) 
WHERE emp.statue=1 
GROUP BY come.uid 
UNION 
SELECT uid,SUM(money) FROM `leave` 
INNER JOIN emp ON ( leave.uid = emp.id ) 
GROUP BY leave.uid 

结果就是这张图片

http://i.stack.imgur.com/xZtO3.jpg

Answer 1

另一种方法（未经测试，如果它爆炸了，请告诉我）：

SELECT emp.id, IF(emp.statue=1, c.sumCome, 0) AS sumCome, l.sumLeave
FROM emp
     LEFT JOIN (SELECT uid, SUM(money) AS sumCome
                FROM come
                GROUP BY uid
               ) c ON emp.id = c.uid
     LEFT JOIN (SELECT uid, SUM(money) AS sumLeave
                FROM leave
                GROUP BY uid
               ) l ON emp.id = l.uid

我不知道哪个会比 Kevin 的更快。你可能想explain他们俩看看。

Answer 2

我们开始：

SELECT q1.uid,SUM(q1.l),SUM(q1.c) FROM
(
SELECT uid,0 as l,SUM(money) as c FROM come 
INNER JOIN emp ON (come.uid = emp.id) 
WHERE emp.statue=1 GROUP BY come.uid 
UNION ALL 
SELECT uid,SUM(money) as l,0 as c FROM leave
INNER JOIN emp ON ( leave.uid = emp.id ) GROUP BY leave.uid 
) q1
GROUP BY uid

Answer 3

试试这个

   select uid,sum(ComeTot),sum(LeaveTot)
   from
  (

    SELECT uid,SUM(money) as ComeTot ,0 as LeaveTot
    FROM come 
    INNER JOIN emp ON(come.uid = emp.id) WHERE emp.statue=1 
    GROUP BY come.uid 
    UNION 
    SELECT uid,0 ,SUM(money) FROM leave
    INNER JOIN emp ON ( leave.uid = emp.id ) 
    GROUP BY leave.uid
  ) xx

GROUP BY xx.uid

我没有在这台 PC 上安装 mySQL，但这应该会让你很接近。根据上述结果，您可能需要将上面的整个查询包装在另一个组中...