select
    e_1.emp_code as "CODE",
    e_1.emp_last_name as "SURNAME",
    e_1.emp_first_name as "NAME"
from emp as e_1
inner join emp as e_2
on
    replace(e_1.emp_last_name, ' ', '') = replace(e_2.emp_last_name, ' ', '')
    and
    replace(e_1.emp_first_name, ' ', '') = replace(e_2.emp_first_name, ' ', '')
    and
    e_1.emp_code != e_2.emp_code
where
    e_1.valid_flg = '1'
order by
    e_1.emp_last_name,
    e_1.emp_code
;