with t1 as (select EMP_CODE, EMP_LAST_NAME, EMP_FIRST_NAME, replace(EMP_LAST_NAME, ' ', '') || replace(EMP_FIRST_NAME,' ', '') as fullname from emp where valid_flg = '1')
, t2 as (select fullname, count(1) as cnt from t1 group by 1)
select 
    t1.EMP_CODE as CODE,
    t1.EMP_LAST_NAME as SURNAME, 
    t1.EMP_FIRST_NAME as NAME
from t1 
inner join t2 using(fullname)
where t2.cnt > 1
order by t1.fullname, 1