条件组在sql server中？

i have this simple query :

我有这个简单的查询：

SELECT YEAR(P.DateCreated)
      ,MONTH(P.DateCreated)
      ,COUNT(*) AS cnt
FROM   tbl1,
       tbl2....
GROUP BY
         MONTH(P.DateCreated)
        ,YEAR(P.DateCreated)
SELE