select
    t1.EMP_CODE as CODE
    ,t1.EMP_LAST_NAME as SURNAME
    ,t1.EMP_FIRST_NAME as NAME
from EMP t1
    inner join EMP t2
    on trim(t1.EMP_LAST_NAME) = trim(t2.EMP_LAST_NAME)
    and trim(t1.EMP_FIRST_NAME) = trim(t2.EMP_FIRST_NAME)
where t1.VALID_FLG = '1'
order by 
    trim(t1.EMP_LAST_NAME)
    ,trim(t1.EMP_FIRST_NAME)
    ,t1.EMP_CODE