# 需求分析，转化率
# 访问id，订单id
# 保留一位小数
# 小数转换成百分位数,乘法100，设置一位，再转化


SELECT a.visit_date as `date`,CONCAT(ROUND(m.cr/a.vr*100,1),'%') as cr
FROM 
(
        SELECT DATE_FORMAT(visit_time,'%Y-%m-%d') AS visit_date,count(distinct user_id) as vr
    from visit_tb a
    group by DATE_FORMAT(visit_time,'%Y-%m-%d')
) a
LEFT JOIN
(
        SELECT DATE_FORMAT(order_time,'%Y-%m-%d') AS order_date,count(distinct user_id) as cr
        from order_tb a  # 表名
        group by DATE_FORMAT(order_time,'%Y-%m-%d')
) m
on a.visit_date=m.order_date
#GROUP BY a.visit_date
order by a.visit_date asc

#结果上，不好看到时间排序和大小降序