with recursive generate_series(value) as (
    select 1
    union all select value+1
    from generate_series
    where value+1<=31)
select
    printf("2022-08-%02d", value) as REGIST_DATE,
    case strftime('%w', printf("2022-08-%02d", value))
        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(USERS.USER_CODE) as TOTAL
from generate_series
left outer join USERS on DATE(USERS.CONFIRMED_AT) = REGIST_DATE and VALID_FLG='1'
group by REGIST_DATE
order by REGIST_DATE