select o_time as date, concat(round(order_num/visit_num*100,1),'%') as cr from
(
select o_time,count(o_time) as order_num from
(
select user_id,date(order_time) as o_time from order_tb
group by user_id,date(order_time)
) as t1
group by o_time
) as t3
join
(
select v_time,count(v_time) as visit_num from
(
select user_id,date(visit_time) as v_time from visit_tb
group by user_id,date(visit_time)
) as t2
group by v_time
) as t4
on t3.o_time = t4.v_time
order by date