select 
    emp_code as CODE,
    emp_last_name as SURNAME,
    emp_first_name as NAME 
from emp 
inner join (
select 
    emp_code as CODE,
    replace(emp_last_name,' ','') as SURNAME,
    replace(emp_first_name,' ','') as NAME 
    from emp 
    where valid_flg='1' 
) as tmp 
on tmp.surname=replace(emp.emp_last_name,' ','')  
and tmp.name=replace(emp.emp_first_name,' ','') 
where valid_flg='1' 
and emp.emp_code<>tmp.code 
order by replace(emp_last_name,' ',''),replace(emp_first_name,' ',''),code;