SELECT 
EMP.EMP_CODE AS CODE,
EMP.EMP_LAST_NAME  AS SURNAME,
EMP.EMP_FIRST_NAME AS NAME
from EMP,
(select replace(EMP_LAST_NAME,' ','')||replace(EMP_FIRST_NAME,' ','') A,count(*)
from EMP
where VALID_FLG = '1'
group by A
having count(*)>1
) S
where replace(EMP.EMP_LAST_NAME,' ','')||replace(EMP.EMP_FIRST_NAME,' ','') = S.A
AND EMP.VALID_FLG = '1'
order by S.A,EMP.EMP_CODE