with a as(
    select  date(order_time) as ot,count(distinct user_id) as order_number
    from order_tb 
    group by date(order_time)
),
b as(
    select date(visit_time) as vt,count(distinct user_id) as v_number
    from visit_tb
    group by date(visit_time)
)
select a.ot as date,
    concat(round(order_number*1.0/v_number*100,1),'%') as cr
from a join b on a.ot=b.vt
order by date