Question

我正在尝试使用B来获取A中特定列的总和和计数，这是另一个表B.CheckerID IS NOT NULL AND A.DBDivRecID='3485'，

所以它会得到A中的总和和数B.CheckerID IS NOT NULL A.DBDivRecID='3485'

我这样做了，但我得到了表A和B的结果，我发现两个表的DBShares列的名称相同，我只想要表A的总DBShares，只需要表B检查CheckerID

SELECT SUM(A.DBShares) As totalshares,COUNT(*) As totalcounts 
FROM ShrDivBenf As A 
INNER JOIN TEMPDRP_3485 AS B ON A.DBDivRecID=B.DBDivRecID 
WHERE B.CheckerID IS NOT NULL AND A.DBDivRecID='3485'

我想要这样的东西（表B中的WHERE CheckerID不为空）

SELECT SUM(A.DBShares) As totalshares,COUNT(*) As totalcounts 
FROM ShrDivBenf As A 
WHERE CheckerID IS NOT NULL

样品

表A

+------------+----------+-------+
| DBDivRecID | DBShares |Name   |
+------------+----------+-------+
|       3485 |     5000 |John   |
|       3485 |     6000 |Mary   |
|       3485 |     7000 |Sam    |
+------------+----------+-------+

表B

+------------+-----------+----------+--------+
| DBDivRecID | CheckerID | DBShares | DBName |
+------------+-----------+----------+--------+
|       3485 |      4555 |     5000 | John   |
|       3485 |      4555 |     6000 | Mary   |
|       3485 |      4555 |     7000 | Sam    |
|       3485 |      NULL |     8000 | Derek  |
+------------+-----------+----------+--------+

让我们说如果我这样做

SELECT A.DbName, A.DbShares 
FROM ShrDivBenf As A 
INNER JOIN TEMPDRP_3485 AS B ON A.DBDivRecID=B.DBDivRecID 
WHERE B.CheckerID IS NOT NULL AND A.DBDivRecID='3485'

我会得到这个（它重复整个事情，即使我的数据库只有1个John，Mary和Sam）

+----------+----------+
| DbName   | DBShares |
+----------+----------+
|  John    |     5000 |
|  Mary    |     6000 |
|  Sam     |     7000 |
|  John    |     5000 |
|  Mary    |     6000 |
|  Sam     |     7000 |
+----------+----------+

Answer 1

由于您有多行具有相同的DBDivRecID，因此您在加入时会获得笛卡尔积。避免这种情况的一种方法是将join替换为in运算符：

SELECT SUM(A.DBShares) As totalshares, COUNT(*) As totalcounts 
FROM   ShrDivBenf
WHERE  DBDivRecID='3485' AND
       DBDivRecID IN (SELECT DBDivRecID 
                      FROM   TEMPDRP_3485
                      WHERE  CheckerID IS NOT NULL)

Answer 2

我想我明白你想要的东西;你正在寻找没有空检查器的记录。鉴于此，请尝试以下方法：

SELECT SUM(A.DBShares) As totalshares, COUNT(*) As totalcounts 
FROM   ShrDivBenf
WHERE  DBDivRecID='3485' AND
   DBDivRecID NOT IN (SELECT DBDivRecID 
                  FROM   TEMPDRP_3485
                  WHERE  CheckerID IS NULL)

SQL查询SELECT计数＆amp;从使用另一个表的表中求和

2 个答案: