Compare Innventory Lists

Every Monday, our database sends me a list in excel, with a snapshot of our inventory.

Here is (simplified) how it looks like

part#, desc, color, units
001 Camry Black 13
003 Toyota Green 2
009 Honda Yellow 17

and so on for about 8k rows.

Every Monday, the list is different. we sold some items, so the "units" in stock are less, we run out of some items, so that part# is not in the list,
we acquired some new items, with a different part#, and new amount of units, some part#s have more units in stock.

I need to send to our boss, a spreadsheet with a list of all part#s in stock every Monday, and the last 4 weeks, how many we sold of each in the last 7 days, so we can try to get rid of inventory that is getting obsolete.

It would be easy to do, if not for the fact of the "new" items that come in, and the items that we run out of, and are not in the list anymore. With 8k items, to to the corrections by hand, it gets old very quickly