Check a value based on product code and date

Hello,

Been looking for a solution for sometime now but not found anything that meets my requirements and hope someone can help!

I receive a file containing invoice details (see tab 'invoices') and I want check the prices are correct against my price file.

My price file has 'standard' prices and another tab showing promotion prices.

What I am trying to do is to take the product code and date from the invoice and find a match from the price file.

Hope I've explained this well enough.

HDD_sheds