如何将下列两个sql 合成一个简单的sql？？？

SELECT DPItemId,COUNT(1) idcount
FROM  T
where     DPDate<='2016-04-15'
group by DPItemId
having count(1) <=10
 ) as t


select count(*)  from (SELECT DPItemId,COUNT(1) idcount
FROM T2
where  DPDate<='2016-04-15'
group by DPItemId
having count(1) >10   
and count(1) <=50
) as t