WITH tmp(CODE, SURNAME, NAME) AS (
    SELECT EMP_CODE CODE, REPLACE(EMP_LAST_NAME, ' ', '') SURNAME, REPLACE(EMP_FIRST_NAME, ' ', '') NAME
    FROM EMP
    WHERE VALID_FLG = '1'
)
SELECT tmp.CODE CODE, tmp.SURNAME SURNAME, tmp.NAME NAME
FROM tmp, (
    SELECT SURNAME, NAME
    FROM tmp
    GROUP BY SURNAME || NAME
    HAVING COUNT(SURNAME || NAME) > 1
) t
WHERE tmp.SURNAME = t.SURNAME AND tmp.NAME = t.NAME
ORDER BY tmp.SURNAME || tmp.NAME ASC, tmp.CODE ASC