"compare" is pretty vague. How about some specifics?
I'd like to automate a process that creates a found set in Table B then based on an ID, confirms that each record in the found set matches the records in Table A
Table A has 15 fields, 10,000 records
Table B has 17 fields, 15,000 records - 15 of the 17 fields are the same as Table A
use a relationship and equi join the fields that are required to match. then put a calc field that looks across the relationship to detect a match