Hi,
I have 2 excel files that have exactly the same format and headings. One is
the reference. What I would like to know is how to use a new file to import
the Reference data with headers and then have this compare the second file by
referencing an ID column and then import the difference in the data from the
second file.

Ie: sh1 has in column 1 a reference 12 /col 2 a number 5 /col 3 a number 87
sh2 has in column 1 a reference 12 /col 2 a number 7 /col 3 a number 56

I would like in my new sheet
sh3 column 1= 12 /col 2= +2 / col3= -31

Thanks
John