下面这种情况下,怎么写Where语句?
表中包含4对字段:
APart1 APart2 BPart1 BPart2 CPart1 CPart2 DPart1 DPart2
现在想找到4对字段完全不相同的记录,
每对字段相同与否的原则是,每对字段对应部分全不相同才认为不等。否则即相等。这样的Where语句怎么写啊?
我的写法是:有社么错误呢?Where
NOT
(
APart1 = BPart1 AND APart2 = BPart2
OR
APart1 = CPart1 AND APart2 = CPart2
OR
APart1 = DPart1 AND APart2 = DPart2
OR
BPart1 = CPart1 AND BPart2 = CPart2
OR
BPart1 = DPart1 AND BPart2 = DPart2
OR
CPart1 = DPart1 AND CPart2 = DPart2
)
表中包含4对字段:
APart1 APart2 BPart1 BPart2 CPart1 CPart2 DPart1 DPart2
现在想找到4对字段完全不相同的记录,
每对字段相同与否的原则是,每对字段对应部分全不相同才认为不等。否则即相等。这样的Where语句怎么写啊?
我的写法是:有社么错误呢?Where
NOT
(
APart1 = BPart1 AND APart2 = BPart2
OR
APart1 = CPart1 AND APart2 = CPart2
OR
APart1 = DPart1 AND APart2 = DPart2
OR
BPart1 = CPart1 AND BPart2 = CPart2
OR
BPart1 = DPart1 AND BPart2 = DPart2
OR
CPart1 = DPart1 AND CPart2 = DPart2
)
where
not ( (A1=B1 and A2=B2)
or (A1=C1 and A2=C2)
or (A1=D1 and A2=D2)
or (B1=C1 and B2=C2)
or (B1=D1 and B2=D2)
or (C1=D1 and C2=D2)
)
Where
(APart1 <> BPart1 or APart2 <> BPart2 )
and
(APart1 = CPart1 or APart2 = CPart2 )
and
(APart1 = DPart1 or APart2 = DPart2)
and
(BPart1 = CPart1 or BPart2 = CPart2 )
and
(BPart1 = DPart1 or BPart2 = DPart2 )
and
(CPart1 = DPart1 or CPart2 = DPart2 )
不过不改了,因为这么该也许还是不对,在这些字段可以null的时候不对null有点复杂,需要确定null是否等于null
Where
NOT
(
(APart1 = BPart1 AND APart2 = BPart2 )
OR
(APart1 = CPart1 AND APart2 = CPart2)
OR
(APart1 = DPart1 AND APart2 = DPart2)
OR
(BPart1 = CPart1 AND BPart2 = CPart2)
OR
(BPart1 = DPart1 AND BPart2 = DPart2)
OR
(CPart1 = DPart1 AND CPart2 = DPart2)
)