addition update; add fieldA value to fieldB, two different tables

[tynus]

Hi,
I'm trying to make a stockroom database such that a value in the [Parts].[Stock_Level] can be added to by the value in [Purchase_Orders].[PO_Quantity] to update stock coming in to the stock. Also to subtract stock when Orders are sent out to customers. [Parts].[Stock_Level]-[Orders].[Order_Quantity]. I have tried to create an update query but the query gives me a dialogue box which tells me... you are about to update 0 row(s) click Yes or No. This is not a helpful dialogue box...
I am starting with very little knowledge or experience...


any help???

[Bob Fitz]

The level of stock is a calculation. It would be better not to save the current level data to a field but calculate it whenever and wherever it is required. See: http://allenbrowne.com/appinventory.html