38 - 换座位

-- 方法一
select
    (
    case
        when id%2=1 and id=(select max(id) from seat) then id
        when id%2=0 then id-1
        else id+1
    end) as id, student
from
    seat
order by
    id;

-- 方法二

select
    if(id%2=0,id-1,if(id=(select max(id) from Seat),id,id+1)) as id,student
from
    Seat
order by 
    id;