2017.04.19:今日头天数据分析笔试02

10.数据库练习

bt.user_visit_log
visit_time（访问时间）	user_id（账号ID）	page_url（访问页量）
2017-03-16 00:59:43	23564	/ad/test1
2017-03-16 01:01:03	94535	/ad/test2
bt.user_register_info
user_id（账号ID）	user_name（账号名称）	reg_time（注册时间）
23564	张三	2014-03-16 21:29:56
94535	李四	2014-12-12 21:45:56

（1）统计该网站每天新注册的用户数量

（2）统计账户名称为“王五”的账户在2017-03-16当天访问最多的页面

（3）统计出2017-03-01到2017-03-16每天访问量最多的ID号

（4）请随机抽取100个2017年新注册的账户

（5）定义指标网站的当月留存率=当月和上月均访问过网站用户数量/上月访问过网站的用户数量；统计2017年3月的留存率。

(1)Select substr(reg_time,1,10) as curr_date, 
      count(1) as daily_add_user_count
   from bt_user_register_info 
   group by substr(reg_time,1,10);
(2)
select page_url
from 
(select
   page_url,
   vsit_count,
   rank() over(order by Visit_count) as rk
from 
   (select 
   a.page_url,
   count(1) as visit_count
   from bt_user_visit_log a
   left join bt_user_register_info b on a.user_id=b.user_id 
   where b.user_name=’王五’
   and substr(a.visit_time,1,10)=’2017-03-16’
   group by a.page_url)c
)d where rk=1
(3)
select user_id
from 
(Select
   user_id,
   visit_count,
   rank() over(order by Visit_count) as rk
from 
   (select 
   a.user_id,
   count(1) as visit_count
   from bt_user_visit_log a
   left join bt_user_register_info b on a.user_id=b.user_id 
   where substr(a.visit_time,1,10)>=’2017-03-01’
   and substr(a.visit_time,1,10)<=’2017-03-16’
   group by a.user_id)c
)d where rk=1
(4) select * from bt_user_register_info where subtr(reg_time,1,4)='2017'order by rand() limit 100; 
(5) select count(1) as two_mon_usercount
    from 
    (select
    substr(a.visit_time,1,7) as month,
    user_id
    from bt_user_visit_log
    where substr(a.visit_time,1,7)='2017-02'
	group by substr(a.visit_time,1,7),user_id)a
	join 
	(select
    substr(a.visit_time,1,7) as month,
    user_id
    from bt_user_visit_log
    where substr(a.visit_time,1,7)='2017-03'
	group by substr(a.visit_time,1,7),user_id)b on (a.user_id=b.user_id)
	
	select count(distinct user_id) as last_mon_user_count
	from bt_user_visit_log
    where substr(a.visit_time,1,7)='2017-02'