现在有一个表Questioin，主码是qid，要求选择第m行到第n行的元组
//方法一：效率最低
//错误：如果n<m，将选取前n条数据，如果n>=m，将选取从m+1开始的n条数据
select top n *
from Question
where qid not in
{
select top m qid
from Question
}
//当然改成下面的就正确了
select top(n-m)*
from Question
where qid not in
(select top m id from Question)
//方法二：先排序，据说效率最高
select top m * from
(select top n * from Question order by qid asc)a
order by qid desc
//方法三：利用ROW_NUMBER函数对元组编号（推荐使用）
SELECT * FROM
(
SELECT ROW_NUMBER() OVER(ORDER BY qid) as rowIndex,* FROM Question
)b
WHERE b.rowIndex>=m AND b.rowindex<=n