T-SQL Group by ？Group by 后的各种类型的前2条数据

T-SQL Group by 求助？Group by 后的各种类型的前2条数据.
SQL：

SQL code


CREATE TABLE [dbo].[USERINFO](
    [USER_ID] [int] IDENTITY(1,1) NOT NULL,
    [ORG_ID] [varchar](64) NOT NULL,
    [USER_NAME] [varchar](128) NOT NULL,
    [USER_SEX] [bit] NULL,
 CONSTRAINT [PK_USERINFO] PRIMARY KEY CLUSTERED 
(
    [USER_ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
SET ANSI_PADDING OFF
GO
SET IDENTITY_INSERT [dbo].[USERINFO] ON
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (1, N'1', N'张三', 1)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (2, N'1', N'李四', 0)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (3, N'1', N'王二', 1)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (4, N'2', N'赵六', 0)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (5, N'2', N'孙五', 0)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (6, N'3', N'马七', 0)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (7, N'3', N'周八', 1)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (8, N'2', N'钱九', 0)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (9, N'3', N'武十', 1)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (10, N'2', N'郑I一', 0)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (11, N'1', N'蒋I二', 1)
INSERT [dbo].[USERINFO] ([USER_ID], [ORG_ID], [USER_NAME], [USER_SEX]) VALUES (12, N'1', N'干I三', 0)
SET IDENTITY_INSERT [dbo].[USERINFO] OFF

Group by [ORG_ID],[USER_NAME] 后，获取[ORG_ID]为1,2,3..n的前2条数据，
即：
[ORG_ID] [USER_NAME]
1 干I三
1 蒋I二
2 钱九
2 孙五
3 马七
3 武十
....

高手请指点一二，小菜拜谢ing...

------解决方案--------------------

SQL code


---------------------------------
--  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)
*/

T-SQL Group by ？Group by 后的各种类型的前2条数据

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