LeetCode 0626 - Exchange Seats
LeetCode 0626 - Exchange Seats
Reck Zhang
发布于 2021-08-11 11:09:30
发布于 2021-08-11 11:09:30
Exchange Seats
Desicription
Mary is a teacher in a middle school and she has a table seat storing students’ names and their corresponding seat ids.
The column id is continuous increment.
Mary wants to change seats for the adjacent students.
Can you write a SQL query to output the result for Mary?
+---------+---------+
| id | student |
+---------+---------+
| 1 | Abbot |
| 2 | Doris |
| 3 | Emerson |
| 4 | Green |
| 5 | Jeames |
+---------+---------+For the sample input, the output is:
+---------+---------+
| id | student |
+---------+---------+
| 1 | Doris |
| 2 | Abbot |
| 3 | Green |
| 4 | Emerson |
| 5 | Jeames |
+---------+---------+Note:
If the number of students is odd, there is no need to change the last one’s seat.
Solution
select
if(id = (select count(*) from seat), if(id % 2 = 0, id - 1, id), if(id % 2 = 0, id - 1, id + 1)) as id, student from seat order by id;本文参与 腾讯云自媒体分享计划，分享自作者个人站点/博客。
原始发表：2019-10-13，如有侵权请联系 cloudcommunity@tencent.com 删除
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