现有订单表orders,包含用户信息userid, 产品信息 productid, 以下()语句能够返回至少被订购过两回的productid?
A. select productid from orders where count(productid)>1
B. select productid from orders wheremax(productid)>1
C. select productid from orders where having count(productid)>1group by product id_
D. select productid from orders group by productid having count(productid)>1