select EMP_CODE as CODE
,EMP_LAST_NAME as SURNAME
,EMP_FIRST_NAME as NAME

from 
EMP A
inner join 
(select replace(EMP_LAST_NAME,' ','') as nm ,replace(EMP_FIRST_NAME,' ','') as nm1,count(*) as cnt from EMP where VALID_FLG='1' 
group by replace(EMP_LAST_NAME,' ',''),replace(EMP_FIRST_NAME,' ','')) b
on nm=replace(EMP_LAST_NAME,' ','') and nm1=replace(EMP_FIRST_NAME,' ','')

where 
a.VALID_FLG = '1' and
b.cnt >1
order by
nm
,EMP_CODE