select 
a.EMP_CODE as CODE,
a.EMP_LAST_NAME as SURNAME,
a.EMP_FIRST_NAME as NAME
  from EMP a,EMP b
 where a.VALID_FLG = '1'
   and b.VALID_FLG = '1'
   and replace(a.EMP_LAST_NAME,' ','')
     = replace(b.EMP_LAST_NAME,' ','')
   and replace(a.EMP_FIRST_NAME,' ','')
     = replace(b.EMP_FIRST_NAME,' ','')
   and a.EMP_CODE < b.EMP_CODE
order by replace(a.EMP_LAST_NAME,' ',''),a.EMP_CODE