leetcode-Database-626|换座位

原题

思路

一

case when

二

注意边界条件

代码

select 
(case  
when  mod(id,2) =1 and id<>(select max(id) from seat ) then id+1
when mod(id,2)=0  then id-1 
else id end 
) AS ID,
student 
from seat
ORDER BY id;