select em.emp_code CODE,
em.emp_last_name SURNAME,
em.emp_first_name NAME
from emp em,(
 select surname, name, cnt from (
 select 
 replace(emp.emp_last_name,' ','') SURNAME,
 replace(emp.emp_first_name,' ','') NAME,
 COUNT(*) CNT
 from emp
 where emp.valid_flg='1'
 group by surname, name
 ) where cnt > 1
) em2
where replace(em.emp_last_name,' ','') = em2.SURNAME and
replace(em.emp_first_name,' ','') = em2.NAME
--and em.valid_flg='1'
order by em2.surname, em.emp_code;