select
    t2.user_id,
    count(distinct t2.sales_date)+1 as days_count
from sales_tb as t1,sales_tb as t2
where t1.user_id = t2.user_id and datediff(t1.sales_date,t2.sales_date) = 1 
group by t2.user_id
order by t2.user_id