WITH RECURSIVE
  cnt(x) AS (VALUES(julianday(replace('2022/08/01', '/', '-') ))
  UNION ALL
   SELECT x+1 FROM cnt WHERE x < julianday(replace('2022/08/31', '/', '-') )),

	 grouping AS (select strftime('%Y-%m-%d', CONFIRMED_AT) as day,
	 count(USER_CODE) as total_count
	from USERS
	where strftime('%Y-%m', CONFIRMED_AT) = '2022-08'
	and VALID_FLG = '1'
	group by strftime('%Y-%m-%d', CONFIRMED_AT))

SELECT strftime('%Y-%m-%d', x) AS REGIST_DATE
, case strftime('%w', x) 
		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' end AS WK
, case when total_count is null then 0 else total_count end as TOTAL
 FROM cnt
left join grouping
on strftime('%Y-%m-%d', x) = day;