select * from table where (时间 between 开始时间 and 结束时间) and (datediff(m,时间,月份) = 0)
//例:
select * from table where (UploadDate between '2008-1-1 00:00' and '2008-1-1 01:00') and (datediff(m,UploadDate,'2008-1-1 00:00'))
//当然开始时间,结束时间的月份和查询的月份要相同

create table testTable
(
    pid int identity (1,1),
    date_created datetime,
    rowid nvarchar(64)
)

insert testTable values (dateadd(hh, 1, getdate()),  cast(newid() as varchar(64)))
insert testTable values (dateadd(hh, 1, getdate()),  cast(newid() as varchar(64)))
insert testTable values (dateadd(hh, 3, getdate()),  cast(newid() as varchar(64)))
insert testTable values (dateadd(hh, 3, getdate()),  cast(newid() as varchar(64)))
insert testTable values (dateadd(hh, 1, getdate()),  cast(newid() as varchar(64)))
insert testTable values (dateadd(hh, 5, getdate()),  cast(newid() as varchar(64)))
insert testTable values (dateadd(hh, 5, getdate()),  cast(newid() as varchar(64)))
insert testTable values (dateadd(hh, 1, getdate()),  cast(newid() as varchar(64)))
insert testTable values (dateadd(hh, 4, getdate()),  cast(newid() as varchar(64)))


select * from testTable

select 
    datepart(MM, date_created) AS [Month], 
    datepart(dd, date_created) AS [Day], 
    datepart(hh, date_created) AS [Hour], 
    count(pid) as ItemCount
from testtable
group by datepart(MM, date_created), datepart(dd, date_created), datepart(hh, date_created)

drop table testTable