need running sum in the same field(circular)

[brown1]

i am new to msaccess.
i want to get a sum of two field and result should be stored in the first field
for example
i have : two fields named availableproduct,, newpurchaseproduct
now i want availableproduct=availableproduct+newpurchaseprodu ct
result should be stored in same location i.e. availableproduct
another two field,, availableproduct,,sellproduct
availableproduct=availableproduct-sellproduct.


please help how do i solve it..

[June7]

Saving aggregate data is usually not a good idea. The saved data can become 'out-of-sync' with the detail records. Are you saving records that are transactions of product sales and purchases? Calculate aggregate data from the raw transactions detail data on reports.

[brown1]

sir , i attached mydb database.. i want purchase_qunty and purchase_amnt as running sum.. every time when i added data through product entry.. this two field summed up with previous data.as well as
when i sell product ,, this two filed subtracted the selling amnt and sell-qunty.
so that i make report of product available in my hand..

[June7]

Review http://www.mrexcel.com/forum/microso...l-records.html