sql问题，急

知道vdsdf 2015-11-17 02:21:58

string sql12=string.Format(@"update Entity_69052 set differencefe=t.chazhi from (
select slotnum
,MAX(CAST(ContentFe AS FLOAT))-MIN(CAST(ContentFe AS FLOAT)) as chazhi
,MAX(ExamineTime) as maxtime from Entity_69052 where ExamineTime<(select Max(ExamineTime) from Entity_69052 where Entity_69051_FK ='{0}')
group by slotnum) t
where Entity_69052.slotnum = t.slotnum and ExamineTime = t.maxtime and t.chazhi is not null",KeyOID);

想求出Entity_69052 中某一时间与某一时间的ContentFe差，赋值给 differencefe ，可是没有赋值，求解答

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Yole 2015-11-17


update a  set a.differencefe=t.chazhi
from Entity_69052 a,
(
select slotnum
,MAX(CAST(ContentFe AS FLOAT))-MIN(CAST(ContentFe AS FLOAT)) as chazhi
,MAX(ExamineTime) as maxtime from Entity_69052  where ExamineTime<(select Max(ExamineTime) from Entity_69052 where Entity_69051_FK ='{0}')
group by slotnum
) t
where a.slotnum = t.slotnum and a = t.maxtime and t.chazhi is not null

语法上没问题~不知道数据是啥样的

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知道vdsdf 2015-11-17

引用 1 楼 u010192842 的回复:


select differencefe
 from (
select slotnum
,MAX(CAST(ContentFe AS FLOAT))-MIN(CAST(ContentFe AS FLOAT)) as chazhi
,MAX(ExamineTime) as maxtime from Entity_69052  where ExamineTime<(select Max(ExamineTime) from Entity_69052 where Entity_69051_FK ='{0}')
group by slotnum) t
where Entity_69052.slotnum = t.slotnum and ExamineTime = t.maxtime and t.chazhi is not null

这个语句您能查到值么？查不到的话自然就没法赋值啊。

感谢你回答我的问题，我想问我写的对不对，，，数据库影噶能查到这个数据，我应该是写错了，求改写 [quote=引用 1 楼 u010192842 的回复:]


select differencefe
 from (
select slotnum
,MAX(CAST(ContentFe AS FLOAT))-MIN(CAST(ContentFe AS FLOAT)) as chazhi
,MAX(ExamineTime) as maxtime from Entity_69052  where ExamineTime<(select Max(ExamineTime) from Entity_69052 where Entity_69051_FK ='{0}')
group by slotnum) t
where Entity_69052.slotnum = t.slotnum and ExamineTime = t.maxtime and t.chazhi is not null

这个语句您能查到值么？查不到的话自然就没法赋值啊。[/quote 感谢你回答我的问题，我想问我写的对不对，，，数据库影噶能查到这个数据，我应该是写错了，求改写

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Yole 2015-11-17


select differencefe
 from (
select slotnum
,MAX(CAST(ContentFe AS FLOAT))-MIN(CAST(ContentFe AS FLOAT)) as chazhi
,MAX(ExamineTime) as maxtime from Entity_69052  where ExamineTime<(select Max(ExamineTime) from Entity_69052 where Entity_69051_FK ='{0}')
group by slotnum) t
where Entity_69052.slotnum = t.slotnum and ExamineTime = t.maxtime and t.chazhi is not null

这个语句您能查到值么？查不到的话自然就没法赋值啊。