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LeetCode: 601. 体育馆的人流量

1、题目描述

X 市建了一个新的体育馆,每日人流量信息被记录在这三列信息中:序号 (id)、日期 (date)、 人流量 (people)。

请编写一个查询语句,找出高峰期时段,要求连续三天及以上,并且每天人流量均不少于100。

例如,表 stadium

+------+------------+-----------+
| id   | date       | people    |
+------+------------+-----------+
| 1    | 2017-01-01 | 10        |
| 2    | 2017-01-02 | 109       |
| 3    | 2017-01-03 | 150       |
| 4    | 2017-01-04 | 99        |
| 5    | 2017-01-05 | 145       |
| 6    | 2017-01-06 | 1455      |
| 7    | 2017-01-07 | 199       |
| 8    | 2017-01-08 | 188       |
+------+------------+-----------+

对于上面的示例数据,输出为:

+------+------------+-----------+
| id   | date       | people    |
+------+------------+-----------+
| 5    | 2017-01-05 | 145       |
| 6    | 2017-01-06 | 1455      |
| 7    | 2017-01-07 | 199       |
| 8    | 2017-01-08 | 188       |
+------+------------+-----------+

Note: 每天只有一行记录,日期随着 id 的增加而增加。

2、解题思路

# Write your MySQL query statement below

select distinct s1.* from stadium s1, stadium s2, stadium s3 where s1.people >= 100 and s2.people >= 100 and s3.people >=100 
and 
(
(s1.id - s2.id = 1 and s2.id - s3.id =1)  
or  
(s2.id - s1.id = 1 and s1.id - s3.id =1)   
or  
(s3.id - s2.id = 1 and s2.id - s1.id = 1)   

)

order by s1.date asc