select 
    a.EMP_CODE as CODE,
    a.EMP_LAST_NAME as SURNAME,
    a.EMP_FIRST_NAME as NAME

from
EMP a inner join EMP b
on replace(a.EMP_LAST_NAME||a.EMP_FIRST_NAME,' ','') = replace(b.EMP_LAST_NAME||b.EMP_FIRST_NAME,' ','')
and a.emp_code != b.emp_code
where 
a.valid_flg='1' and b.valid_flg='1'
order by 
replace(a.EMP_LAST_NAME||a.EMP_FIRST_NAME,' ','') 
, a.emp_code