WITH old_set AS (SELECT first_name, last_name
                   FROM addresses 
                  WHERE status = 1),

     new_set AS (SELECT first_name, last_name
                   FROM temp_load_table)

SELECT COUNT(src1) AS in_old_set,
       COUNT(src2) AS in_new_set,
       first_name,
       last_name
  FROM (SELECT first_name, last_name, 1 AS src1, TO_NUMBER(NULL) AS src2
          FROM old_set
        UNION ALL
        SELECT first_name, last_name, TO_NUMBER(NULL) AS src1, 2 AS src2 FROM new_set)
 GROUP BY first_name, last_name
HAVING COUNT(src1) <> COUNT(

This compares selected columns between 2 queries, using the WITH clause.  It lists the rows and values that are different between the two sources.

This is from Tom Kyte (www.asktom.com).  I can't say I understand exactly how it works, but it's much faster than other methods I've seen, because it only looks through each query once.

Efficiently compare results from two queries

PL/SQL