SELECT
    LOGIN_DATETIME FIRST_LOGIN,
    COUNT(MEMBER_CODE) MEMBER_CNT
FROM
    (
    SELECT 
        MEMBER_CODE, MIN(LOGIN_DATETIME) LOGIN_DATETIME
    FROM
        ACCESS_LOG
    GROUP BY MEMBER_CODE
    ) T
WHERE
     LOGIN_DATETIME BETWEEN "2023-08-01" AND "2023-08-31"
GROUP BY FIRST_LOGIN
ORDER BY LOGIN_DATETIME DESC