create a formula in query or report in access for inventory

[Luddy]

I need help to create a formula in query or in the report for a decrease in inventory status after an order is entered.
I did create one in excel and i would like to duplicate this in the query if it can be done.

Example: IN EXCEL =J2-SUMIF(C$2:sC2,C2,G2:G2)

......C2.............................. G2............... J2....... K2
[Part Number] [Date] [Quantity Ordered] [InStock] [Stock Left]
848888...........4-3-14.......... 100....................200..........100<-------------after order is in
848888...........5-2-14.......... 50......................200......... 50
848888...........6-2-14.......... 75......................200.........-25


55000............4-30-14.........300.....................400..........100
55000............5-29-14..........200....................400.........-100

I am sending a Attachment as well to show what i did in excel.
So I need a formula to work in access query or report if it can be done.

Thank you

[June7]

Would have to know more about the Access structure.

Consider http://allenbrowne.com/AppInventory.html

Have you looked at the Access Desktop Product Inventory Database template?