--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
取出分组后每组的第一条记录（不用group by）按时间排序
原文：http://www.cnblogs.com/lgx5/p/6411832.html