select
    t1.emp_code "CODE"
    ,t1.emp_last_name "SURNAME"
    ,t1.emp_first_name "NAME"
from
    emp t1 cross join emp t2
where
    t1.valid_flg = '1'
    and t2.valid_flg = '1'
    and t1.emp_code <> t2.emp_code
    and replace(t1.emp_last_name, ' ', '') = replace(t2.emp_last_name, ' ', '')
    and replace(t1.emp_first_name, ' ', '') = replace(t2.emp_first_name, ' ', '')
order by
    replace(t1.emp_last_name, ' ', '') || replace(t1.emp_first_name, ' ', '')
    ,replace(t2.emp_last_name, ' ', '') || replace(t2.emp_first_name, ' ', '')
    ,t1.emp_code
    ,t2.emp_code
;