create table OriginalData
(  PerNo int identity(1,1) primary key,  
PerID nvarchar(20),  Status int,  
CheckTime   datetime  )  
INSERT INTO OriginalData
SELECT 's001',1,'2007-06-11 08:01' UNION ALL
SELECT 's001',1,'2007-06-11 09:02' UNION ALL
SELECT 's001',0,'2007-06-11 10:05' UNION ALL
SELECT 's001',0,'2007-06-11 11:40' UNION ALL
SELECT 's001',1,'2007-06-11 12:00' UNION ALL
SELECT 's001',0,'2007-06-11 12:42' UNION ALL
SELECT 's001',1,'2007-06-11 13:58' UNION ALL
SELECT 's001',0,'2007-06-11 14:50' UNION ALL
SELECT 's001',0,'2007-06-11 15:00' UNION ALL
SELECT 's001',1,'2007-06-11 16:00' UNION ALL
SELECT 's001',1,'2007-06-11 16:30' UNION ALL
SELECT 's001',0,'2007-06-11 17:50' UNION ALL
SELECT 's001',0,'2007-06-11 18:00'   
当有相邻的1或0时，查询出时间小的那个。查询出的结果是1，0，1，0，1....