求一条查询语句！
ID Name height class
1 张三 180 1
2 李四 182 1
3 王五 178 2
4 曹六 184 3
5 刘德华 175 4
6 张学友 174 4
7 周杰伦 173 4
8 陈柏霖 180 3
9 冯德伦 173 3
.. .. .. ..
用一条语句查询出每个班级最高的两位同学
[解决办法]
select * from tb
t
where height in(select top 2 height from tb where class=t.class)
select *
from tb t
where id in(select top 2 from tb where t.class=class order by height desc)
select * from TAB as T where height in(select top 2 height from TAB where class=T.class)
select t.* from tb t where height in (select top 2 height from tb where class = t.class)
---N种方法
---------------------------------
-- Author: liangCK 小梁
-- Title : 查每个分组前N条记录
-- Date : 2008-11-13 17:19:23
---------------------------------
--> 生成测试数据: #T
IF OBJECT_ID('tempdb.dbo.#T') IS NOT NULL DROP TABLE #T
CREATE TABLE #T (ID VARCHAR(3),GID INT,Author VARCHAR(29),Title VARCHAR(39),Date DATETIME)
INSERT INTO #T
SELECT '001',1,'邹建','深入浅出SQLServer2005开发管理与应用实例','2008-05-10' UNION ALL
SELECT '002',1,'胡百敬','SQLServer2005性能调校','2008-03-22' UNION ALL
SELECT '003',1,'格罗夫Groff.J.R.','SQL完全手册','2009-07-01' UNION ALL
SELECT '004',1,'KalenDelaney','SQLServer2005技术内幕存储引擎','2008-08-01' UNION ALL
SELECT '005',2,'Alex.Kriegel.Boris.M.Trukhnov','SQL宝典','2007-10-05' UNION ALL
SELECT '006',2,'飞思科技产品研发中心','SQLServer2000高级管理与开发','2007-09-10' UNION ALL
SELECT '007',2,'胡百敬','SQLServer2005数据库开发详解','2008-06-15' UNION ALL
SELECT '008',3,'陈浩奎','SQLServer2000存储过程与XML编程','2005-09-01' UNION ALL
SELECT '009',3,'赵松涛','SQLServer2005系统管理实录','2008-10-01' UNION ALL
SELECT '010',3,'黄占涛','SQL技术手册','2006-01-01'
--SQL查询如下:
--按GID分组,查每个分组中Date最新的前2条记录
--1.字段ID唯一时:
SELECT * FROM #T AS T WHERE ID IN(SELECT TOP 2 ID FROM #T WHERE GID=T.GID ORDER BY Date DESC)
--2.如果ID不唯一时:
SELECT * FROM #T AS T WHERE 2>(SELECT COUNT(*) FROM #T WHERE GID=T.GID AND Date>T.Date)
--SQL Server 2005 使用新方法
--3.使用ROW_NUMBER()进行排位分组
SELECT ID,GID,Author,Title,Date
FROM
(
SELECT rid=ROW_NUMBER() OVER(PARTITION BY GID ORDER BY Date DESC),*
FROM #T
) AS T
WHERE rid<=2
--4.使用APPLY
SELECT DISTINCT b.*
FROM #T AS a
CROSS APPLY
(
SELECT TOP(2) * FROM #T WHERE a.GID=GID ORDER BY Date DESC
) AS b
--结果
/*
ID GID Author Title Date
---- ----------- ----------------------------- --------------------------------------- -----------------------
003 1 格罗夫Groff.J.R. SQL完全手册 2009-07-01 00:00:00.000
004 1 KalenDelaney SQLServer2005技术内幕存储引擎 2008-08-01 00:00:00.000
005 2 Alex.Kriegel.Boris.M.Trukhnov SQL宝典 2007-10-05 00:00:00.000
007 2 胡百敬 SQLServer2005数据库开发详解 2008-06-15 00:00:00.000
009 3 赵松涛 SQLServer2005系统管理实录 2008-10-01 00:00:00.000
010 3 黄占涛 SQL技术手册 2006-01-01 00:00:00.000
(6 行受影响)
*/
if not object_id('tb') is null
drop table tb
Go
Create table tb([ID] int,[Name] nvarchar(3),[height] int,[class] int)
Insert tb
select 1,N'张三',180,1 union all
select 2,N'李四',182,1 union all
select 3,N'王五',178,2 union all
select 4,N'曹六',184,3 union all
select 5,N'刘德华',175,4 union all
select 6,N'张学友',174,4 union all
select 7,N'周杰伦',173,4 union all
select 8,N'陈柏霖',180,3 union all
select 9,N'冯德伦',173,3
Go
Select *
from tb t
where (select count(*) from tb where [class]=t.[class] and [height]>t.[height] )<2
/*
ID Name height class
----------- ---- ----------- -----------
1 张三 180 1
2 李四 182 1
3 王五 178 2
4 曹六 184 3
5 刘德华 175 4
6 张学友 174 4
8 陈柏霖 180 3
(7 個資料列受到影響)
*/select t.* from tb t where height in (select top 2 height from tb where class = t.class order by height desc)
Create table tb([ID] int,[Name] nvarchar(3),[height] int,[class] int)
Insert tb
select 1,N'张三',180,1 union all
select 2,N'李四',182,1 union all
select 3,N'王五',178,2 union all
select 4,N'曹六',184,3 union all
select 5,N'刘德华',175,4 union all
select 6,N'张学友',174,4 union all
select 7,N'周杰伦',173,4 union all
select 8,N'陈柏霖',180,3 union all
select 9,N'冯德伦',173,3
go
select t.* from tb t where height in (select top 2 height from tb where class = t.class order by height desc)
drop table tb
/*
ID Name height class
----------- ---- ----------- -----------
1 张三 180 1
2 李四 182 1
3 王五 178 2
4 曹六 184 3
5 刘德华 175 4
6 张学友 174 4
8 陈柏霖 180 3
（所影响的行数为 7 行）
*/
select *
from tb t
where id in(select top 2 id from tb where t.class=class order by height desc)