SELECT
    EMP1.EMP_CODE AS CODE,
    EMP1.EMP_LAST_NAME AS SURNAME,
    EMP1.EMP_FIRST_NAME AS NAME
FROM
    EMP EMP1
    LEFT OUTER JOIN EMP EMP2 ON
        TRIM(REPLACE(EMP1.EMP_LAST_NAME, ' ', '')) = TRIM(REPLACE(EMP2.EMP_LAST_NAME, ' ', '')) AND
        TRIM(REPLACE(EMP1.EMP_FIRST_NAME, ' ', '')) = TRIM(REPLACE(EMP2.EMP_FIRST_NAME, ' ', '')) AND
        EMP1.EMP_CODE < EMP2.EMP_CODE
WHERE
    EMP1.VALID_FLG = '1' AND
    EMP2.EMP_CODE IS NULL
ORDER BY
    TRIM(REPLACE(EMP1.EMP_LAST_NAME, ' ', '')) ASC,
    TRIM(REPLACE(EMP1.EMP_FIRST_NAME, ' ', '')) ASC,
    EMP1.EMP_CODE ASC;