SELECT
 EMP_CODE AS CODE
,E.EMP_LAST_NAME AS SURNAME
,E.EMP_FIRST_NAME AS NAME
FROM EMP E
LEFT JOIN 
(SELECT REPLACE(EMP_LAST_NAME,' ','') || REPLACE(EMP_FIRST_NAME,' ','') NAME
,COUNT(*) NUM FROM EMP
WHERE VALID_FLG='1'
 GROUP BY REPLACE(EMP_LAST_NAME,' ','') || REPLACE(EMP_FIRST_NAME,' ','')) L
ON REPLACE(E.EMP_LAST_NAME,' ','') || REPLACE(E.EMP_FIRST_NAME,' ','') = L.NAME
WHERE L.NUM>1
ORDER BY REPLACE(E.EMP_LAST_NAME,' ','') || REPLACE(E.EMP_FIRST_NAME,' ','') ,EMP_CODE