LeetCode 1132.申请的报告2

数据准备

Create table If Not Exists Actions (user_id int, post_id int, action_date date, action ENUM('view', 'like', 'reaction', 'comment', 'report', 'share'), extra varchar(10));
create table if not exists Removals (post_id int, remove_date date);
Truncate table Actions;
insert into Actions (user_id, post_id, action_date, action, extra) values ('1', '1', '2019-07-01', 'view', 'None');
insert into Actions (user_id, post_id, action_date, action, extra) values ('1', '1', '2019-07-01', 'like', 'None');
insert into Actions (user_id, post_id, action_date, action, extra) values ('1', '1', '2019-07-01', 'share', 'None');
insert into Actions (user_id, post_id, action_date, action, extra) values ('2', '2', '2019-07-04', 'view', 'None');
insert into Actions (user_id, post_id, action_date, action, extra) values ('2', '2', '2019-07-04', 'report', 'spam');
insert into Actions (user_id, post_id, action_date, action, extra) values ('3', '4', '2019-07-04', 'view', 'None');
insert into Actions (user_id, post_id, action_date, action, extra) values ('3', '4', '2019-07-04', 'report', 'spam');
insert into Actions (user_id, post_id, action_date, action, extra) values ('4', '3', '2019-07-02', 'view', 'None');
insert into Actions (user_id, post_id, action_date, action, extra) values ('4', '3', '2019-07-02', 'report', 'spam');
insert into Actions (user_id, post_id, action_date, action, extra) values ('5', '2', '2019-07-03', 'view', 'None');
insert into Actions (user_id, post_id, action_date, action, extra) values ('5', '2', '2019-07-03', 'report', 'racism');
insert into Actions (user_id, post_id, action_date, action, extra) values ('5', '5', '2019-07-03', 'view', 'None');
insert into Actions (user_id, post_id, action_date, action, extra) values ('5', '5', '2019-07-03', 'report', 'racism');
Truncate table Removals;
insert into Removals (post_id, remove_date) values ('2', '2019-07-20');
insert into Removals (post_id, remove_date) values ('3', '2019-07-18');

需求

编写一段 SQL 来查找：在被报告为垃圾广告的帖子中，被移除的帖子的每日平均占比，四舍五入到小数点后 2 位。

输入

分析

输出

-- 编写一段 SQL 来查找：在被报告为垃圾广告的帖子中，被移除的帖子的每日平均占比，四舍五入到小数点后 2 位。
with t1 as (
   select *
    from Actions
    where extra='spam'
),t2 as (
    select t1.*,r.post_id as post_r_id
    from t1 left join Removals r
    on t1.post_id=r.post_id
),t3 as (
    select action_date,count(post_id) as cnt1,count(post_r_id) as cnt2
    from t2
    group by action_date
)
select round(avg(cnt2/cnt1),2) as average_daily_percent
from t3
;