WITH
    TMP AS (
        SELECT
            EMP_CODE AS CODE,
            EMP_LAST_NAME AS SURNAME,
            EMP_FIRST_NAME AS NAME,
            VALID_FLG AS VALID_FLG,
            REPLACE (EMP_LAST_NAME, ' ', '') AS TMP_L,
            REPLACE (EMP_FIRST_NAME, ' ', '') AS TMP_F
        FROM
            EMP
    )
SELECT
    t1.CODE AS CODE,
    t1.SURNAME AS SURNAME,
    t1.NAME AS NAME
FROM
    TMP AS t1
    INNER JOIN TMP AS t2 ON t1.CODE != t2.CODE
    AND t1.TMP_L = t2.TMP_L
    AND t1.TMP_F = t2.TMP_F
    AND t2.VALID_FLG = 1
WHERE
    t1.VALID_FLG = 1
ORDER BY
    t1.TMP_L ASC,
    t1.CODE ASC;