with base as (
  select
    emp_code as CODE
    , emp_last_name as SURNAME
    , emp_first_name as NAME
    , replace(emp_last_name, ' ', '') || replace(emp_first_name, ' ', '') as full_name
  from
    emp
  where
    valid_flg = '1'
)

, base2 as (
  select
    base.*
    , count(*) over (partition by full_name) as cnt
  from base
)

select
  CODE
  , SURNAME
  , NAME
from base2
where cnt > 1
order by full_name, CODE