SQL SERVER 取重复值和取某列第N大值得行数据的 SQL语句

SQL SERVER 取重复值和取某列第N大值得行数据的 SQL语句

举例：

创建一学生表结构如下：

create Table Student
(
[id] [int] IDENTITY(1,1) NOT NULL,
[name] [varchar](20) NOT NULL,
[age] [int] NOT NULL
)

插入如下数据：

insert into Student([name],age) values('小明',24);
insert into Student([name],age) values('小红',34);
insert into Student([name],age) values('小至',22);
insert into Student([name],age) values('小黄',22);
insert into Student([name],age) values('小王',34);
insert into Student([name],age) values('小刘',26);
insert into Student([name],age) values('小天',27);
insert into Student([name],age) values('小地',24);

那么我们要获取Student表中年龄第3大的学生数据该怎么写查询呢？ 如下：

//方法一（只能显示一条数据）
select top 1 t.* from (select TOP 3 * from Student a
where a.id in(select top 1 id from Student where age =a.age )
order by age DESC,id) t order by age

//方法二（可查询出所有并列第N大的数据行，如果有的话）
select * from student where age =(select top 1 age from student
where age in(select top 3 age from Student group by age order by age desc)
order by age asc)

那我们又要获取Student表中所有同龄学生的数据该怎么写呢？如下：

select * from Student
where age in(select age from Student group by age having count(age) > 1)
order by age