SELECT date(CONFIRMED_AT) AS REGIST_DATE, 
    case strftime('%w', date(CONFIRMED_AT))
        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,
    COUNT(date(CONFIRMED_AT)) AS TOTAL
    FROM USERS
    WHERE CONFIRMED_AT IS NOT NULL AND CONFIRMED_AT BETWEEN '2022-08-01 00:00:00' AND '2022-08-31 23:59:59' AND VALID_FLG = 1
    GROUP BY date(CONFIRMED_AT);