with temp as (select date(visit_time) as date_visit,count(distinct user_id) as visit_count
from  visit_tb
group by date(visit_time)
),
temp2 as (
    select date(order_time) as date_order,count(distinct user_id) as order_count
from  order_tb
group by date(order_time)
)
select t1.date_visit as date,concat(round(order_count/visit_count*100,1),'%') as cr
from temp2 t2
join temp t1 on t1.date_visit=t2.date_order;