select 
date(CONFIRMED_AT) AS REGIST_DATE,
case strftime('%w', 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(*) AS TOTAL
from USERS
where CONFIRMED_AT >= "2022-08-01" AND CONFIRMED_AT <= "2022-08-31" AND CONFIRMED_AT not null
group by date(CONFIRMED_AT)