with T1 as (
    select date(o.order_time) as day,count(distinct(o.user_id)) as orderdone
    from order_tb o
    group by (date(o.order_time))
),T2 as (
    select date(v.visit_time) as day,count(distinct(v.user_id)) as ordertot
    from visit_tb v
    group by (date(v.visit_time))
)

select 
t2.day as date, concat(round(t1.orderdone/t2.ordertot*100,1),'%') as cr
from T2 t2 left join T1 t1 on t1.day=t2.day