select
  a.EMP_CODE as "CODE"
 ,a.EMP_LAST_NAME as "SURNAME"
 ,a.EMP_FIRST_NAME as "NAME"
from
 (
  select
    EMP_CODE
   ,EMP_LAST_NAME
   ,EMP_FIRST_NAME
   ,replace(EMP_LAST_NAME, ' ', '') || replace(EMP_FIRST_NAME, ' ', '') as "FULLNAME"
  from
   EMP
  where
   VALID_FLG = '1'
 ) a
join
 (
  select
    EMP_CODE
   ,EMP_LAST_NAME
   ,EMP_FIRST_NAME
   ,replace(EMP_LAST_NAME, ' ', '') || replace(EMP_FIRST_NAME, ' ', '') as "FULLNAME"
  from
   EMP
  where
   VALID_FLG = '1'
 ) b
on
 a.EMP_CODE = b.EMP_CODE
order by
 a."FULLNAME" asc, a.EMP_CODE asc
;