取出分组后每组的第一条记录（不用group by）按时间排序

--操作日志表

CREATE TABLE [dbo].[JobLog](

[JobLogId] [int] IDENTITY(1,1) NOT NULL,

[FunctionId] [nvarchar](20) NULL,

[OperateTime] [datetime]
NULL,

CONSTRAINT [PK_JobLog]
PRIMARY KEY CLUSTERED

(

[JobLogId] 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

-- 操作日志表的所有记录

select *
from JobLog

查询结果：

1 001 2007-11-01

2 001 2007-11-02

3 001 2007-11-03

4 002 2007-11-04

5 002 2007-11-05

6 003 2007-11-06

7 004 2007-11-07

8 004 2007-11-08

9 005 2007-11-09

10 005 2007-11-10

-- 每个功能最后一次操作记录

SELECT * FROM JobLog A

WHERE JobLogId in

(SELECT TOP
1 JobLogId FROM
JobLog WHERE A.FunctionId = FunctionId ORDER BY OperateTime DESC)

查询结果：

3 001 2007-11-03

5 002 2007-11-05

6 003 2007-11-06

8 004 2007-11-08

10 005 2007-11-10