select 
    EMP_CODE as CODE,
    EMP_LAST_NAME as SURNAME,
    EMP_FIRST_NAME as NAME
from EMP
where VALID_FLG = 1
and (replace(SURNAME, " ", ""), replace(NAME, " ", "")) in 
(
    select 
    replace(EMP_LAST_NAME, " ", ""),
    replace(EMP_FIRST_NAME, " ", "")
    
    from EMP
    where VALID_FLG = 1
    and EMP_CODE != CODE
)

order by 
(replace(SURNAME, " ", "") asc,
CODE asc
;