SQL"；除「；还有问题吗

我有一个查询引擎历史数据的SQL数据库。其中一个特性是，存储过程每天都会搜索特定事件的所有数据，如果找到该事件，则会将其插入到新表中

问题是这些数据必须是唯一的

表格标题如下：

ID / ID_Location / IDDown / IDUp / DtDown / DtUp / TimeDifference / IsExempt / Reason / Details / OrigDtUp 

SQL查询是：

insert into exempts(ID_Location, iddown, idup, dtdown, dtup, timedifference) 
select ID_Location, iddown, idup, dtdown, dtup, DATEDIFF(MINUTE, dtdown, dtup) as timedifference 
from @tmptbl 
except 
select ID_Location, iddown, idup, dtdown, dtup, timedifference from exempts 

用户可以对其中一些值进行调整，例如DtUp（发动机重新联机的时间）。更改DtUp值后，原始DtUp值存储在OrigDtUp字段中，并根据DtDown和DtUp时间变化更新时差

所以我真正需要的是：

insert into exempts(ID_Location, iddown, idup, dtdown, dtup, timedifference) 
select ID_Location, iddown, idup, dtdown, dtup, DATEDIFF(MINUTE, dtdown, dtup) as timedifference 
from @tmptbl 
except 
select ID_Location, iddown, idup OR OrigDtUp, dtdown, dtup from exempts

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我们知道SQL中的

except

函数不支持它？？？

您不能将其删除两次吗

insert into exempts(ID_Location, iddown, idup, dtdown, dtup, timedifference) 
select ID_Location, iddown, idup, dtdown, dtup, DATEDIFF(MINUTE, dtdown, dtup) as timedifference 
from tmptbl 
except 
select ID_Location, iddown, idup, dtdown, dtup 
from exempts
except 
select ID_Location, iddown, OrigDtUp, dtdown, dtup 
from exempts

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完美的谢谢你的帮助！！