I have a question and need you help in it. The situation is:

I am working with an excel file containing 3 main sheets: Products - Purchase - Sale.
When I receive a new product I have to add the code and name of it to the Product sheet first, then enter the code and purchased quantity to the Purchase sheet.

When a product is sold I just have to scan the code of the given product to the Sale sheet and add the sold quantity.

What I would like to do is to not have to put in the sold quantity manually (espacially with small amount e.g. 1,2,3 pcs), but only by scanning the product code with the given times.

For example if I sold 3 pieces of Product1, then I have to scan the code of Product1 three times, and in the Quantity column it will appears "3", so I don't have to put it in manually.

The other problem is that the same product can be sold several times a day to different customers, and I don't want those quantities to add up, so it should be stayes seperated by customers and dates as well.

I would appreciate any kind of help.

Thank you in advance.
I attach a sample file similar to the one I am using right now.