怎样取出如下数据

[NMGYUE]

数据库表结构：
id sessionid username password starttime endtime indexNO
1 20080314001 helo 123 2008-03-14 09:32:32 2008-03-14 09:35:31 1
2 20080314001 helo 123 2008-03-14 09:32:32 2008-03-14 09:35:31 2
3 20080314002 dawei 123 2008-03-14 10:33:34 2008-03-14 10:34:20 1
4 20080314003 nik 123 2008-03-14 11:05:53 2008-03-14 11:12:52 1
5 20080314004 shure 123 2008-03-14 17:01:26 2008-03-14 17:01:48 1
6 20080314004 mky 123 2008-03-14 17:01:26 2008-03-14 17:01:48 2

写个Sql语句，按sessionid分组，显示记录，显示格式如下：
20080314001
helo 123 2008-03-14 09:32:32 2008-03-14 09:35:31 1
helo 123 2008-03-14 09:32:32 2008-03-14 09:35:31 2
20080314002
dawei 123 2008-03-14 10:33:34 2008-03-14 10:34:20 1
20080314003
nik 123 2008-03-14 11:05:53 2008-03-14 11:12:52 1
20080314004
shure 123 2008-03-14 17:01:26 2008-03-14 17:01:48 1
mky 123 2008-03-14 17:01:26 2008-03-14 17:01:48 2

[-狙击手-]

select seessionid,username,password,stattime,endtime,indexno
from ta
group by seessionid,username,password,stattime,endtime,indexno with rollup
having not (grouping(username)=1 and grouping(password)=1 and grouping(stattime)=1 and grouping(endtime)=1 and grouping(indexno)=0 and grouping(seessionid)=0)