WITH
    F_LOGIN AS(
        SELECT MEMBER_CODE
             , MIN(LOGIN_DATETIME) AS F_LOGIN_DATETIME
          FROM ACCESS_LOG
         GROUP BY MEMBER_CODE
    )

SELECT DATE(A.F_LOGIN_DATETIME) AS FIRST_LOGIN
     , COUNT(A.MEMBER_CODE)     AS MEMBER_CNT
  FROM F_LOGIN AS A
 WHERE STRFTIME('%m', A.F_LOGIN_DATETIME) = '08'
GROUP BY FIRST_LOGIN
ORDER BY FIRST_LOGIN DESC
;