leetcode mysql 626. 换座位

#考虑最大值

select

     case     when (id%2) = 1 and id < num then id+1

              when (id%2) = 0 and id < num then id-1

               else id end

     as id,student

 from Seat,(select max(id) as num  from Seat) a

 order by  id

#不考虑最大值

select rank() over(order by change_id) as  id,student

from

(select

    case  when (id%2)=1 then id+1

          when (id%2)=0 then id-1

          end  as change_id,student

from Seat) t

注：本报产生的临时表