SELECT
    EMP_CODE AS CODE
    ,EMP_LAST_NAME AS SURNAME
    ,EMP_FIRST_NAME AS NAME
FROM
    EMP
WHERE
    VALID_FLG = 1
    AND replace(EMP_LAST_NAME || EMP_FIRST_NAME, ' ', '') IN (
                --サブクエリで姓名をスペース削除の後、繋げる。姓名毎にグループピングして2つ以上あるものを抽出
                SELECT
                    replace(EMP_LAST_NAME || EMP_FIRST_NAME, ' ', '')
                FROM
                    EMP
                WHERE
                    VALID_FLG = 1
                GROUP BY
                    replace(EMP_LAST_NAME || EMP_FIRST_NAME, ' ', '')
                HAVING
                    COUNT(*) >= 2
                )
ORDER BY
    replace(EMP_LAST_NAME || EMP_FIRST_NAME, ' ', '') ASC
    ,CODE ASC;