WITH subq AS (
--直近2回の体重を会員ごとに抽出
    SELECT
        CHECKUP_DATE AS DATE
        ,HEALTH_CHECKUP.MEMBER_CODE AS M_CODE
        ,MEMBER_MST.LAST_NAME || MEMBER_MST.FIRST_NAME AS NAME
        ,WEIGHT AS 今回体重
        ,LAG(WEIGHT, 1) OVER (
            PARTITION BY HEALTH_CHECKUP.MEMBER_CODE
            ORDER BY HEALTH_CHECKUP.CHECKUP_DATE
            ) AS 直前体重
    FROM
        HEALTH_CHECKUP
    INNER JOIN
        MEMBER_MST
      ON
        HEALTH_CHECKUP.MEMBER_CODE = MEMBER_MST.MEMBER_CODE
    )

SELECT
    DATE AS CK_DATE
    ,M_CODE AS CODE
    ,NAME
    ,ROUND([今回体重] - [直前体重], 1) AS CHG_WT
FROM
    subq
WHERE
    [今回体重] - [直前体重] IS NOT NULL
    AND ABS(ROUND([今回体重] - [直前体重], 1)) >= 5
ORDER BY
    CHG_WT DESC
    ,CODE DESC;