$ and查询不返回结果

好吧，这杀了我.也许已经晚了，我忘记了一些东西，但这应该可行.

Ok this one is killing me. Maybe its late and I am forgetting something, but this should work.

出于测试目的，我的收藏中大约有6000个文档.有一个名为Priority的属性，每个实例的值均为2.

For test purposes, I have about 6000 documents in my collection. There is a property called Priority which has a value of 2 in every instance.

以下两个查询均返回全部 6000个文档:

The following two queries each return all 6000 documents:

{
    Priority: {
        $gt: 1
    }
}

和

{
    Priority: {
        $lt: 10
    }
}

但是，此查询返回0个结果，并且根据说明，对所有6000个文档进行了全面扫描:

This query, however, returns 0 results and according to the Explain, does a full scan of all 6000 documents:

{
$and: [
        {
            Priority: {
                $gt: 1
            }
        },
        {
            Priority: {
                $lt: 10
            }
        }
    ]
}

我错过了什么吗?