[SQL] 取连续符合条件的值

表:Stadium
+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| id            | int     |
| visit_date    | date    |
| people        | int     |
+---------------+---------+
visit_date 是表的主键
每日人流量信息被记录在这三列信息中:序号 (id)、日期 (visit_date)、 人流量 (people)
每天只有一行记录,日期随着 id 的增加而增加

建表语句及数据:

Create table If Not Exists stadium (id int, visit_date DATE NULL, people int)
Truncate table stadium
insert into stadium (id, visit_date, people) values ('1', '2017-01-01', '10')
insert into stadium (id, visit_date, people) values ('2', '2017-01-02', '109')
insert into stadium (id, visit_date, people) values ('3', '2017-01-03', '150')
insert into stadium (id, visit_date, people) values ('4', '2017-01-04', '99')
insert into stadium (id, visit_date, people) values ('5', '2017-01-05', '145')
insert into stadium (id, visit_date, people) values ('6', '2017-01-06', '1455')
insert into stadium (id, visit_date, people) values ('7', '2017-01-07', '199')
insert into stadium (id, visit_date, people) values ('8', '2017-01-09', '188')

要求:

编写一个 SQL 查询以找出每行的人数大于或等于 100 且 id 连续的三行或更多行记录。
返回按 visit_date 升序排列的结果表。

结果如下:

Stadium table:
+------+------------+-----------+
| id   | visit_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    | 2017-01-09 | 188       |
+------+------------+-----------+

Result table:
+------+------------+-----------+
| id   | visit_date | people    |
+------+------------+-----------+
| 5    | 2017-01-05 | 145       |
| 6    | 2017-01-06 | 1455      |
| 7    | 2017-01-07 | 199       |
| 8    | 2017-01-09 | 188       |
+------+------------+-----------+
id 为 5678 的四行 id 连续,并且每行都有 >= 100 的人数记录。
请注意,即使第 7 行和第 8 行的 visit_date 不是连续的,输出也应当包含第 8 行,因为我们只需要考虑 id 连续的记录。
不输出 id 为 23 的行,因为至少需要三条 id 连续的记录。
 

答案:

with t1 as(
    select a.*,row_number() over(order by id) as r, id - row_number() over(order by id) as rk
    from tmp_sxy_leetc a 
    where people >= 100
)

select id,visit_date,people
from t1
where rk in(
    select rk
    from t1
    group by rk
    having count(rk) >= 3
)
;

题目来源:LeetCode - 体育馆人流量

原文地址:https://www.cnblogs.com/x-you/p/14846455.html