select * from tb查询结果
c1 c2 c3
------------
1 aa aa
1 bb bb
1 cc cc
2 dd dd
2 ee ee
2 ff ff
3 gg gg我现在想根据c1列,查询出根据c1分组的数据的前2条
(c1为1有3条,那我只要2条 c1为2的也有3条,也只要2条 就是这样子)
结果应该是
c1 c2 c3
------------
1 aa aa
1 bb bb
2 dd dd
2 ee ee
3 gg gg
c1 c2 c3
------------
1 aa aa
1 bb bb
1 cc cc
2 dd dd
2 ee ee
2 ff ff
3 gg gg我现在想根据c1列,查询出根据c1分组的数据的前2条
(c1为1有3条,那我只要2条 c1为2的也有3条,也只要2条 就是这样子)
结果应该是
c1 c2 c3
------------
1 aa aa
1 bb bb
2 dd dd
2 ee ee
3 gg gg
where [c2]+[c3] in(select top 2 [c2]+[c3] from [tb] where [c1]=t.[c1])
from tb a
where 2>(select count(*) from tb where c1=a.c1 and c2<a.c2)
-- 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)
*/
(
c1 int,
c2 nchar(10),
c3 nchar(10)
)
insert into #YY2 select 1,'aa','aa'
insert into #YY2 select 1,'bb','bb'
insert into #YY2 select 1,'cc','cc'
insert into #YY2 select 2,'dd','dd'
insert into #YY2 select 2,'ee','ee'
insert into #YY2 select 2,'ff','ff'
insert into #YY2 select 3,'gg','gg'select *,identity(int,1,1) rank into # from #YY2
select c1,c2,c3 from
(
select *,
(select count(*) from # where c1=Y.c1 and rank<y.rank) num
from # y
) tt
where num<2
c1 c2 c3
----------- ---------- ----------
1 aa aa
1 bb bb
2 dd dd
2 ee ee
3 gg gg
select *,identity(int,1,1) rank into # from #YY2
select c1,c2,c3 from
(
select *,
(select count(*) from # where c1=Y.c1 and rank<y.rank) num
from # y
) tt
where num<2
--2
select *,identity(int,1,1) rank into # from #YY2
select c1,c2,c3 from # y
cross APPLY
(
select count(*) num from # where c1=Y.c1 and rank<y.rank
) num
where num<2
c1 c2 c3
----------- ---------- ----------
1 aa aa
1 bb bb
2 dd dd
2 ee ee
3 gg gg
CREATE TABLE tb(c1 INT,c2 VARCHAR(2),c3 CHAR(2))
INSERT INTO tb
SELECT 1, 'aa' , 'aa' UNION all
SELECT 1 , 'bb' , 'bb' UNION all
SELECT 1 , 'cc' , 'cc' UNION all
SELECT 2 , 'dd' , 'dd' UNION all
SELECT 2 , 'ee' , 'ee' UNION all
SELECT 2 , 'ff' , 'ff' UNION all
SELECT 3 , 'gg' , 'gg' SELECT * FROM tb SELECT TOP 2 * FROM tb WHERE c1 IN(SELECT TOP 2 c1 FROM tb WHERE c1=1 )
UNION all
SELECT TOP 2 * FROM tb WHERE c1 IN(SELECT TOP 2 c1 FROM tb WHERE c1=2)
UNION ALL
SELECT * FROM tb WHERE c1=3