I am hoping somebody can tell me if it is possible to create a report that produces a running total using data from two independent tables.

 

I have three tables in total:

 

1:  A Stock table with the details of each stock item and it's current "On hand" quantity.

 

2:  A Sales Order table with a record for each stock item sold, the quantity required and its delivery date.

 

3:  A Purchase Order table with a record for each stock item on order from our suppliers and the date it is due into store.

 

I am trying to generate a report which will produce an "On Hand" running total for each stock item and print a record when the "Stock on Hand" falls to zero or below. I need to start with the Stock on Hand quantity subtract the sales and add the purchases in date order. Is it possible? Am I missing something? Thanks in advance.....