compare files again

Is it possible to look at two data files, look at the data and if a record is missing from one of the files show which record is missing. I only want to compare the record count then show the missing record.

I have used diff, but one of the files would be processed before checking and some minor changes can happen to the data fields.

Perhaps you could use join -v instead of diff?

You may want to use:

comm file1 file2