interface for comparing differences between two data structures

My input is 2 or more tables, where each table has the following format:

I need to show the user which entry numbers are different between the tables (which entries are not identical with respect to the field values) along with the changes themselves. The main issue is that these tables can get very big (up to 128K entries). The basic UI I thought of doing something like this:

User will choose the entry number he wishes to see and it will display this entry for all of the tables. But how do I notify about which entries are relevant? A drop-down menu with the entry numbers? The tables could have differences in thousands of entries. From one side I don't want to clog the screen with long lists of numbers but I also don't want the user to scroll endlessly to reach his entry of interest. Would love your input.

P.S. the Excel tables are just for illustration. This has nothing to do with Excel.