with a as(
select EMP_CODE, replace(EMP_LAST_NAME, ' ', '') as la, replace(EMP_FIRST_NAME, ' ', '') as fi, replace(EMP_LAST_NAME, ' ', '')||replace(EMP_FIRST_NAME, ' ', '') as name, VALID_FLG  
from EMP 
where VALID_FLG='1'
), b as (
select name, count(*) from a
group by name
having count(*) > 1
), c as(
select * from a
where name in (select name from b)
 and VALID_FLG='1'
)

select EMP_CODE as CODE, EMP_LAST_NAME as SURNAME, EMP_FIRST_NAME as NAME from EMP
where EMP_CODE in (select EMP_CODE from c)
 and VALID_FLG='1'
;