with T as (select emp_code, replace(EMP_FIRST_NAME, ' ', '') as FN, replace(EMP_LAST_NAME, ' ', '') as LN
           from emp
           where VALID_FLG = '1')

select distinct emp.emp_code as CODE , EMP_LAST_NAME, EMP_FIRST_NAME
from emp inner join T as T1 on emp.emp_code=T1.emp_code
    inner join T as T2 on emp.emp_code <> T2.emp_code
    and T1.FN=T2.FN and T1.LN=T2.LN
where emp.VALID_FLG = '1'

order by (T1.LN||T2.FN), emp.emp_code
;