SELECT
        O.CUST_CODE AS CODE
       ,C.CUST_NAME AS NAME
       ,COUNT(DISTINCT O.ORDER_DATE) AS CNT
    FROM
        CUSTOMER C
       ,ORDERS   O
    WHERE
        -- 受注日が2023-07-01から2023-07-31
        O.ORDER_DATE BETWEEN '2023-07-01' AND '2023-07-31'
    AND O.CUST_CODE = C.CUST_CODE
    GROUP BY
        O.CUST_CODE
       ,C.CUST_NAME
    ORDER BY
        CNT DESC
       ,CODE DESC