SELECT
  EMP_CODE AS CODE,
  EMP.EMP_LAST_NAME AS SURNAME,
  EMP.EMP_FIRST_NAME AS NAME
FROM
  EMP 
INNER JOIN(
    SELECT
      EMP_LAST_NAME,
      EMP_FIRST_NAME,
      COUNT(*) AS CNT
    FROM
      EMP
    WHERE EMP.VALID_FLG = '1'
    GROUP BY
      REPLACE(EMP_LAST_NAME," ",""),
      REPLACE(EMP_FIRST_NAME," ","")
    HAVING COUNT(*) > 1
      )a
ON REPLACE(EMP.EMP_LAST_NAME," ","") = a.EMP_LAST_NAME
AND REPLACE(EMP.EMP_FIRST_NAME," ","") = a.EMP_FIRST_NAME
ORDER BY REPLACE(EMP.EMP_LAST_NAME," ","") || REPLACE(EMP.EMP_FIRST_NAME," ",""),
         EMP_CODE