WITH TO_COMPARE AS(
SELECT EMP_CODE AS CODE, EMP_LAST_NAME AS SURNAME, EMP_FIRST_NAME AS NAME,
REPLACE(EMP_LAST_NAME,' ','') AS TRIMED_LAST, REPLACE(EMP_FIRST_NAME,' ','') AS TRIMED_FIRST 
FROM EMP
WHERE VALID_FLG = '1'
)

SELECT CODE,SURNAME,NAME FROM TO_COMPARE
WHERE TRIMED_LAST IN(
SELECT TRIMED_LAST
FROM TO_COMPARE
GROUP BY TRIMED_LAST
HAVING COUNT(TRIMED_LAST) > 1
) AND
TRIMED_FIRST IN(
SELECT TRIMED_FIRST
FROM TO_COMPARE
GROUP BY TRIMED_FIRST
HAVING COUNT(TRIMED_FIRST) > 1
)
ORDER BY SURNAME, NAME,CODE