Find out the users who log in for 7 consecutive days and 30 consecutive days

Little red book written test , Telecom cloud interview ：

/* use dw; SELECT * from fct_sales fs limit 10; SELECT min(dimDateID) , max(dimDateID) from fct_sales fs limit 10; -- 20170602 20170830 */

select * ,count(1)over() as cnt
from 
	(
		select   user_id
		        ,dts
		        ,count(1) as num
		from 
			(
				select  user_id
				       ,date_sub(log_in_date, interval ranks day) dts
				from 
					(
					SELECT  user_id 
					       ,log_in_date
					       ,row_number()over(partition by user_id order by log_in_date asc) as ranks
					from (
							select DISTINCT  dimMemberID as user_id, date(dimDateID) as log_in_date
							from fct_sales
							where timestampdiff(day, date(dimDateID),(select max(dimDateID) from fct_sales)) <=  30
							      and  dimMemberID <> 0	
					      ) data_source
				     ) t
			) a 
		group by  user_id,dts	 
	) b
where num in (7,30);