请教这句SQL,好象难度挺大的

Question

按小时  
select distinct StatDate,BtNum1,GnutellaNum1,TEdonkeyNum1,UEdonkeyNum1,BaiduNum1 
from nt_p2p_hour_traffic
where StatDate between '2005-06-05' and '2005-06-06'
order by StatDate desc
按天数
select distinct substr(StatDate,1,8),BtNum1,GnutellaNum1,TEdonkeyNum1,UEdonkeyNum1,BaiduNum1 
from nt_p2p_hour_traffic
where StatDate between '2005-06-06' and '2005-07-06'
order by substr(StatDate,1,8) desc

Answer 1

bumblebeelyh(大黄蜂) 的 2应该为：
select substr(StatDate,1,8),sum(BtNum1),sum(GnutellaNum1),sum(TEdonkeyNum1),sum(UEdonkeyNum1),sum(BaiduNum1)
from nt_p2p_hour_traffic
where StatDate between '2005-06-06' and '2005-07-06'
group by (StatDate,1,8)
order by substr(StatDate,1,8) desc

Answer 2

上面有误  ~
bumblebeelyh(大黄蜂) 的按天数应该为：
select substr(StatDate,1,8),sum(BtNum1),sum(GnutellaNum1),sum(TEdonkeyNum1),sum(UEdonkeyNum1),sum(BaiduNum1)
from nt_p2p_hour_traffic
where StatDate between '2005-06-06' and '2005-07-06'
group by substr(StatDate,1,8)
order by substr(StatDate,1,8) desc