select
    emp_code "CODE"
    ,emp_last_name "SURNAME"
    ,emp_first_name "NAME"
from
    emp
where
    valid_flg = '1'
    and replace(emp_last_name, ' ', '') || replace(emp_first_name, ' ', '')
    in(
        select
            replace(emp_last_name, ' ', '') || replace(emp_first_name, ' ', '') fullname
        from
            emp
        where
            valid_flg = '1'
        group by
            fullname
        having
            count(*) >= 2
    )
    
order by
    replace(emp_last_name, ' ', '') || replace(emp_first_name, ' ', '')
    ,emp_code
;