Doing a comparison on two csv files with no Primary Key
If you have your first CSV loaded into a table, you can just as easily load the other one into a staging table (presumably with the same structure as the 'real' one).  Then you can get the new rows by

SELECT * FROM staging_table
EXCEPT
SELECT * FROM real_table
;


Rows missing from the new CSV can be get reversing the two sides around EXCEPT.  However, given the lack of a key on the staging table (and hopefully not on the real one - it's not clear from your question), deleting rows based on this comparison can be painful, especially with so many rows.

You can drop the staging table once you have finished.

(As far as I see, this approach will work in any RDBMS.)