Compare two files

I have 2 files and they both have work hours in days by columns. I want to compare the work hours base on names and project numbers. The names and project numbers do not match, but I have a mapping sheet to convert one to the other. After both sheet have been compared, I need the result to give me back the Name, Project Number, date, and work hours that is different from both file.

I'm comparing Data_Entry to Invoice_Name.
for Project Name, use the Project name tab
for Name use use Vendor ID to Invoice Name.