求SQL语名统计数据，弄半天了，没解决

declare @t1 table(id int,ext varchar(10),[time] datetime)insert into @t1 (id,ext,[time])values(0,'a','2012-04-10 13:20:04.000')insert into @t1 (id,ext,[time])values(0,'a','2012-04-10 14:29:12.000')insert into @t1 (id,ext,[time])values(0,'a','2012-04-25 18:29:34.000')insert into @t1 (id,ext,[time])values(1,'b','2012-04-25 14:03:18.000')insert into @t1 (id,ext,[time])values(1,'b','2012-04-25 10:53:08.000')insert into @t1 (id,ext,[time])values(1,'b','2012-04-30 11:51:38.000')insert into @t1 (id,ext,[time])values(1,'c','2012-04-30 12:09:36.000')insert into @t1 (id,ext,[time])values(1,'c','2012-04-30 17:04:05.000')select * from @t1-----所要的结果-------id ext count time--0 a 2 2012-04-10--0 a 1 2012-04-25--1 b 2 2012-04-25--1 b 1 2012-04-30--1 c 2 2012-04-30select id,ext,count(id) as [count] ,convert(varchar(10),[time],120) as [Time] from @t1group by id,ext,convert(varchar(10),[time],120)-----------------------------id          ext        time----------- ---------- -----------------------0           a          2012-04-10 13:20:04.0000           a          2012-04-10 14:29:12.0000           a          2012-04-25 18:29:34.0001           b          2012-04-25 14:03:18.0001           b          2012-04-25 10:53:08.0001           b          2012-04-30 11:51:38.0001           c          2012-04-30 12:09:36.0001           c          2012-04-30 17:04:05.000(8 行受影响)id          ext        count       Time----------- ---------- ----------- ----------0           a          2           2012-04-100           a          1           2012-04-251           b          2           2012-04-251           b          1           2012-04-301           c          2           2012-04-30(5 行受影响)