SELECT
    OD.CUST_CODE AS CODE
    , CS.CUST_NAME AS NAME
    , COUNT(OD.ORDER_NO) AS CNT
    , SUM(OD.ORDER_AMNT) AS TTL_AMT
    -- 平均受注金額をROUND関数で四捨五入（小数点第1位のためパラメータを省略）
    , ROUND(AVG(OD.ORDER_AMNT)) AS AVG_AMT 
FROM
    ORDERS AS OD 
    -- 顧客名を取得するため、顧客テーブルを内部結合
    INNER JOIN CUSTOMER AS CS 
        ON CS.CUST_CODE = OD.CUST_CODE 
WHERE
    OD.ORDER_DATE BETWEEN '2023-09-01' AND '2023-09-30' 
GROUP BY
    OD.CUST_CODE
    , CS.CUST_NAME 
-- 受注件数が5件以上の顧客のみ対象
HAVING
    CNT >= 5 
ORDER BY
    CNT DESC
    , AVG_AMT DESC
    , CODE ASC
-- 上位5件まで表示
LIMIT 5;