select 
    EMP_CODE as CODE,
    EMP_LAST_NAME as SURNAME,
    EMP_FIRST_NAME as NAME
from emp
where VALID_FLG=1
    and replace(EMP_LAST_NAME||EMP_FIRST_NAME,' ','') in (
        select replace(EMP_LAST_NAME||EMP_FIRST_NAME,' ','') as EMP_NAME
        from emp
        where
            VALID_FLG=1
        group by EMP_NAME
        having count(*)>=2
    )
order by replace(EMP_LAST_NAME||EMP_FIRST_NAME,' ','') asc,EMP_CODE asc