I have two large files that I want to compare by a customer number.

If the customer number is in the one file, I want to be able to identify the
missing customer number in the second file.

If the second file has a customer number plus another cell of information
(i.e. customer level), and the person is not in the first file, I know that
that person is no longer a valid customer. I need to delete that customer's
information from the second file.

However, if the customer does not have anything in the customer level column
on the first file and his name does not appear on the second file, I know
that the customer is "new" and just needs to be added to the second file.

I can not figure out how to get the two files to process this comparison.

--
Doc