select name,sum(num),format(date,'%Y-%m')
from table1
where date between '2012-02-01' and '2012-02-29'
group by name
having sum(num)>=2

------解决方案--------------------
select name,sum(num),'2012-02'
from table1
where date >'2012-02-01' and date<'2012-03-01'
group by name
having sum(num)>=2