有订单表order,包含用户信息uid, 商品信息gid, 以下( )语句能够返回至少被购买两次的商品id。 A.SELECT gid FROM order WHERE COUNT(gid)>1; B.SELECT gid FROM order WHERE MAX(gid)>1; C.SELECT gid FROM order GROUP BY gid HAVING COUNT(gid)>1; D.SELECT gid FROM order WHERE HAVING COUNT(gid)>1 GROUP BY gid;