Question

以下是我正在处理的查询：

SELECT  TBL_SUB_KEY AS port
      , poe.[TBL_COMPANY]
      , poe.[TBL_DIVISION_1]
FROM    dbo.TMVKTAB AS poe
WHERE   ( TBL_NUMBER = '8A' )
        AND ( TBL_SUB_KEY <> '' )
        AND ( poe.[TBL_COMPANY] <> '011'
              AND poe.[TBL_DIVISION_1] <> '11'
            )

我想要归还的是公司='011'/ Division_1'= '11'中不的所有记录。

我认为在（）中组合公司/部门会实现这一点，但事实并非如此。它消除了所有公司的'011'记录，并且它消除了所有分区'11'记录。

然而，当我这样做时：

SELECT  TBL_SUB_KEY AS port
      , poe.[TBL_COMPANY]
      , poe.[TBL_DIVISION_1]
FROM    dbo.TMVKTAB AS poe
WHERE   ( TBL_NUMBER = '8A' )
        AND ( TBL_SUB_KEY <> '' )
        AND NOT ( poe.[TBL_COMPANY] = '011'
              AND poe.[TBL_DIVISION_1] = '11'
            )

它似乎能够得出正确的结果。这是为什么？

Answer 1

这是一个布尔逻辑问题：

NOT (A and B) <=> NOT A  OR NOT B

即：

NOT ( poe.[TBL_COMPANY] = '011' AND poe.[TBL_DIVISION_1] = '11')

相当于：

( poe.[TBL_COMPANY] <> '011' OR poe.[TBL_DIVISION_1] <> '11')

读：

http://en.wikipedia.org/wiki/Boolean_logic

Answer 2

我认为NOT的等价物将使用OR，如下所示：

SELECT  TBL_SUB_KEY AS port
      , poe.[TBL_COMPANY]
      , poe.[TBL_DIVISION_1]
FROM    dbo.TMVKTAB AS poe
WHERE   ( TBL_NUMBER = '8A' )
        AND ( TBL_SUB_KEY <> '' )
        AND ( poe.[TBL_COMPANY] <> '011'
              OR poe.[TBL_DIVISION_1] <> '11'
            )

Answer 3

where x and (y and z)

与

相同

x and y and z

然而

where x and not (y and z)

是你想要的，也是有效的。

试试这个：

SELECT  TBL_SUB_KEY AS port
      , poe.[TBL_COMPANY]
      , poe.[TBL_DIVISION_1]
FROM    dbo.TMVKTAB AS poe
WHERE   ( TBL_NUMBER = '8A' )
        AND ( TBL_SUB_KEY <> '' )
        AND NOT ( poe.[TBL_COMPANY] = '011'
                  AND poe.[TBL_DIVISION_1] = '11'
                )

Answer 4

一些布尔代数的时间。这样：

not (x and y)

与：

相同

(not x or not y)

所以你的查询应该是：

SELECT  TBL_SUB_KEY AS port
      , poe.[TBL_COMPANY]
      , poe.[TBL_DIVISION_1]
FROM    dbo.TMVKTAB AS poe
WHERE   ( TBL_NUMBER = '8A' )
        AND ( TBL_SUB_KEY <> '' )
        AND ( poe.[TBL_COMPANY] <> '011'
              OR poe.[TBL_DIVISION_1] <> '11'
            )

Answer 5

因为不属于两者公司011和第11部分的记录与

相匹配

          poe.[TBL_COMPANY] <> '011'
          OR poe.[TBL_DIVISION_1] <> '11'

如果公司不是011，分区可以是11，你仍然会有匹配组合。

De Morgan's law解释了如何以这种方式转换布尔表达式。

SQL WHERE使用AND和NOT排除记录

5 个答案: