declare @Start varchar(10)
declare @End varchar(10)
set @Start='2012-04'
set @End='2013-09'
--实现跨年:
select 
    convert(varchar(7),DATEADD(MM,number,cast(@Start+'-01' as date)),120) as Year_Month
from 
    master..spt_values
where 
    number between 0 
    and DATEDIFF(MM,cast(@Start+'-01' as date),cast(@End+'-01' as date))
    and type='p'

/*
Year_Month
------------------
2012-04
2012-05
2012-06
2012-07
2012-08
2012-09
2012-10
2012-11
2012-12
2013-01
2013-02
2013-03
2013-04
2013-05
2013-06
2013-07
2013-08
2013-09
*/