SELECT
    EMP.EMP_CODE AS CODE
  , EMP.EMP_LAST_NAME AS SURNAME
  , EMP.EMP_FIRST_NAME AS NAME
FROM
    EMP
    LEFT JOIN(
      SELECT
          REPLACE((EMP_LAST_NAME || EMP_FIRST_NAME), " ", "") AS full_name
          , COUNT(EMP_CODE) AS count
      FROM EMP
      WHERE
         VALID_FLG = '1'
      GROUP BY
           full_name
    ) EMP2
    ON REPLACE((EMP.EMP_LAST_NAME || EMP.EMP_FIRST_NAME), " ", "") = EMP2.full_name
WHERE EMP.VALID_FLG = '1'
  AND EMP2.count > 1
ORDER BY
    EMP2.full_name ASC
  , EMP.EMP_CODE ASC