如果您有一个附加的序列列(例如UniqeID)，这将很容易.如果有的话，就可以这样

 更新 CumulativeTable
     SET 累积=值+(选择 Sum(Value)从累积表其中 UniqueID< c.UniqueID
                         AND  ID = c.ID)
来自 CumulativeTable c 

或者如果没有，可以尝试一下，

  DECLARE   @ TempTable   TABLE (唯一ID  int   IDENTITY ，
ID  int ，
值数字( 18 ， 3 )，
累积数字( 18 ， 3 )
)

 DECLARE   @ TempTable   TABLE (唯一ID  int   IDENTITY ，
ID  int ，
值数字( 18 ， 3 )，
累积数字( 18 ， 3 )
)

插入 插入  @ TempTable (ID，值，累计)
选择 ID，值，累积从累积表

更新 CumulativeTable
 SET 累积=  COALESCE (c.Value +( Select  Sum(Value)来自  @ TempTable  其中 UniqueID< c.UniqueID
 AND  ID = c.ID)， 0 )
来自 CumulativeTable t， @ TempTable  c
位置 t.ID = c.ID  AND  t.Value = c.Value 

但是如果您有多个具有相同ID和值的记录，这将无法为您提供正确的值​​lockquote>

Hi,
I am having trouble writing a query that accurately does what I need.
I have a table like the following

Id    Date        Value     Cumulative
1     Jan 1st       0.2
2     Jan 1st       0.5
1     Jan 2nd       0.7
2     Jan 2nd       0.6
4     Jan 2nd       0.1
1     Jan 3rd       0.02
3     jan 3rd      0.01
4     Jan 3rd      0.03

I want to write a query which inserts the cumulative column with the sum of the value for the same Ids i.e.,

Id     Cumulative
1        0.2
2        0.5
1        0.9  (0.2+0.7)
2        1.1  (0.5+0.6)
4        0.1
1        0.92  (0.2+0.7+0.02)
3        0.01
4        0.13  (0.1 + 0.03)

Thanks in advance.

It would be easy if you have an additional sequence column (e.g. UniqeID). If you have, you can just have it this way

Update CumulativeTable
    SET Cumulative = Value + (Select Sum(Value) From CumulativeTable Where UniqueID < c.UniqueID
                        AND ID = c.ID)
From CumulativeTable c

or if you don''t have, you can try this,

DECLARE @TempTable TABLE (UniqueID int IDENTITY,
ID int,
Value numeric(18,3),
Cumulative numeric(18,3)
)

DECLARE @TempTable TABLE (UniqueID int IDENTITY,
ID int,
Value numeric(18,3),
Cumulative numeric(18,3)
)

Insert Into @TempTable (ID, Value, Cumulative)
Select ID, Value, Cumulative From CumulativeTable

Update CumulativeTable
	SET Cumulative = COALESCE(c.Value + (Select Sum(Value) From @TempTable Where UniqueID < c.UniqueID
						AND ID = c.ID),0)
From CumulativeTable t, @TempTable c
Where t.ID = c.ID AND t.Value = c.Value

but this will not give you correct value if you have multiple records with the same ID and value