WITH cleansed AS(
SELECT 
EMP_CODE AS CODE,
replace(EMP_LAST_NAME, " ", "")||replace(EMP_FIRST_NAME, " ", "") AS FULL_NM,
EMP_LAST_NAME AS SURNAME,
EMP_FIRST_NAME AS NAME
FROM EMP
WHERE VALID_FLG = "1"
),
count_tbl as(
SELECT a.FULL_NM, count(a.FULL_NM) as cnt
FROM cleansed as a
JOIN cleansed as b
ON a.FULL_NM = b.FULL_NM
GROUP BY a.FULL_NM
)

SELECT CODE, SURNAME, NAME
FROM cleansed 
WHERE FULL_NM IN (SELECT FULL_NM FROM count_tbl WHERE cnt >1)
ORDER BY FULL_NM ASC, CODE ASC