with tmp as(
    select 
        emp_code as CODE,
        replace(emp_last_name,' ','') as SURNAME,
        replace(emp_first_name,' ','') as NAME,
        replace(emp_last_name || emp_first_name,' ','') as EMP_NAME
    from
        emp
    where
        VALID_FLG = '1'
    )

select
    t1.CODE as CODE,
    t1.SURNAME as SURNAME,
    t1.NAME as NAME
from
    tmp as t1
    inner join tmp as t2
        on t1.CODE != t2.CODE
        and t1.EMP_NAME = t2.EMP_NAME
order by
    t1.EMP_NAME ASC,
    t1.CODE ASC
;