WITH DATES as (
            select 
                date( (select min(date(CONFIRMED_AT)) from users), '+' || (rownum - 1) || ' days') as CALDATE
            from (
                select row_number() over win as rownum
                from users
                window win as (order by user_code)
            )
            WHERE
            CALDATE BETWEEN date('2022-08-01') AND date('2022-08-31')
        )

        select 
            CALDATE as REGIST_DATE
            , case strftime('%w', CALDATE)
                    when '0' then '日'
                    when '1' then '月'
                    when '2' then '火'
                    when '3' then '水'
                    when '4' then '木'
                    when '5' then '金'
                    when '6' then '土'
                    else 'undefined'
                end as WK
            , IFNULL( TOTAL, 0 ) as TOTAL
        From
        DATES LEFT JOIN  
        (
            select
                date(CONFIRMED_AT) CONFIRMED_AT, 
                COUNT(USER_CODE) as TOTAL
            from
                USERS
            WHERE valid_flg = '1'
            GROUP BY
                date(CONFIRMED_AT)
        ) TOTAL ON CALDATE = date(CONFIRMED_AT)
        ORDER BY CALDATE