Sql Server统计表中某年某月某个值有多少？

比如：统计表AA中YWLX列在某年某月每种类型各有多少？

select
year(AA_YWRQ) as YEARS,
  month(AA_YWRQ) AS Months ,AA_YWLX,count(AA_YWLX) as Number 
from  AA
group by year(AA_YWRQ),
  month(AA_YWRQ),AA_YWLXselect
year(A