How to sum up previous rows value with current row in ms access query?

Question

The input is as follows:

name  |  qty  
-------------
 A    |   10   
 B    |   20  
 C    |   20

The output should be:

Name    |  qty
---------------
 A      |   10
 B      |   30
 C      |   50

=>for first row the score should come as it is..

=>for second row it should be the sum of previous row and the current row..

=>for third row it should be the sum of the previous 2 rows and the current row..

How to write a ms access query for this one.. Help me out..

Thanks in advance...

Answer 1

Finally I got Answer....

(SELECT (IIF(ISNULL(((SELECT Sum(PROCESS.QTY) AS STOCK FROM PROCESS WHERE PROCESS.id <= BAL.id ))),0,((SELECT Sum(PROCESS.QTY) AS STOCK FROM PROCESS WHERE PROCESS.id <= BAL.id ) ))) FROM PROCESS AS BAL )