Countif using a changing date range and unique values

[irampuria1]

I am building a KPI dashboard using data pulled from external sources - one of the metrics I am trying to measure is "No. of Unique Invoices" (in essence the number of distinct & unique orders) received per week. We have a spreadsheet with the "Shipping Date" in Column A, "Product Name" in Column B and "Invoice No." in Column E, since multiple products may be bought under the same invoice number.

A B E
11/01 Product A 1
11/13 Product A 2
11/23 Product B 2
11/24 Product A 2
11/26 Product B 3
11/26 Product C 3

What I am trying to do is have the "Weekly No. of Unique Invoices" update automatically whenever the sheet is refreshed based on the "TODAY()" date. For the week of the 11/26, the Unique No. of Invoices per week would be "2." I need a formula that can (1) look up the date in column A to isolate the range as being between today() and today()-7, and (2) then count the number of distinct invoice numbers within that range of dates.

Sorry for the convoluted explanation, but this has been a tricky process to reconcile.

Thanks in advance for any help.

 

[Rijnsent]

Hi Irampuria,
something like this?
=COUNTIFS(A2:A13,"<="&TODAY(),A2:A13,">="&TODAY()-7)
Cheers,
Koen