一个基本的sql查询

aoteman_prc 2011-04-02 09:43:10

小弟现在有一个小问题，想要一个sql，
ID Title Type
1 AAA 1
2 AA1 2
3 AA2 3
4 AA3 1
5 AA4 2
6 AA5 3
7 AA6 1
8 AA7 2
9 AA8 3
10 AA9 1
11 A10 2
12 A12 3
13 A13 1
14 A14 2
15 A15 3

想用一句sql取得如下的结果
Title Type
AAA 1
AA3 1
AA1 2
AA4 2
AA5 3
AA8 3
就是根据type取每个Type最新的两条记录,求各位大侠们指教

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--小F-- 2011-04-02

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select

   *

from

   tb a

cross apply

   (select top 2 * from tb where type=a.type order by type )b

--小F-- 2011-04-02

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---------------------------------

--  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)

*/

天-笑 2011-04-02

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declare @t table (id int , title varchar(8),type int)

insert into @t

select 1,'AAA',1 union all

select 2,'AA1',2 union all 

select 3,'AA2',3 union all 

select 4,'AA3',1 union all 

select 5,'AA4',2 union all 

select 6,'AA5',3 union all 

select 7,'AA6',1 union all 

select 8,'AA7',2 union all 

select 9,'AA8',3 union all 

select 10,'AA9',1 union all 

select 11,'A10',2 union all 

select 12,'A11',3 union all 

select 13,'A12',1 union all 

select 14,'A13',2 union all 

select 15,'A14',3 



;with t as (

select RANK() over (PARTITION  by type order by type ,id) as no ,* from @t )



select * from t where no <=2



----------------------



1	1	AAA	1

2	4	AA3	1

1	2	AA1	2

2	5	AA4	2

1	3	AA2	3

2	6	AA5	3

chuanzhang5687 2011-04-02

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select t.* from tb t where id in 

(select top 2 id from tb where Type = t.Type order by id) 

order by t.type , t.id

dawugui 2011-04-02

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create table tb(ID int,Title varchar(10),Type int)

insert into tb values(1  ,'AAA', 1)

insert into tb values(2  ,'AA1', 2)

insert into tb values(3  ,'AA2', 3)

insert into tb values(4  ,'AA3', 1)

insert into tb values(5  ,'AA4', 2)

insert into tb values(6  ,'AA5', 3)

insert into tb values(7  ,'AA6', 1)

insert into tb values(8  ,'AA7', 2)

insert into tb values(9  ,'AA8', 3)

insert into tb values(10 ,'AA9', 1)

insert into tb values(11 ,'A10', 2)

insert into tb values(12 ,'A12', 3)

insert into tb values(13 ,'A13', 1)

insert into tb values(14 ,'A14', 2)

insert into tb values(15 ,'A15', 3)

go



select t.* from tb t where id in (select top 2 id from tb where Type = t.Type order by id) order by t.type , t.id



drop table tb



/*

ID          Title      Type        

----------- ---------- ----------- 

1           AAA        1

4           AA3        1

2           AA1        2

5           AA4        2

3           AA2        3

6           AA5        3



（所影响的行数为 6 行）

*/