如何使用PHP Mongo从文档中获取嵌套数组

这里我有两个文档，我需要查询以获得title="post one"和comments: userid="1"，我只想获得具有上述标准的评论。不是所有的注释。

' {" _id ": ObjectId (" 53 b7f2383ed7755c2400002e "),"title":"Post One";"作者":"鲍勃","发布":ISODate("2014 - 07 - 05 t12:40:24.0z"),"页面浏览量":NumberInt (5),"评论":{" 0 ": {"标识":"1","text": "this is cool"}，" 1 ": {"标识":"2","text": "这很糟糕"}，" 3 ": {"标识":"3","text": "this is badexample"}" 4 ": {"标识":"4","text": "不，谢谢"}" 5 ": {"标识":"1","text": "不，很好"}" 6 ": {"标识":"1","文本":"测试"}" 7 ": {"标识":"1","text": "不，很好，还不错"}" 8 ": {"标识":"1","text": "Testing ddd"}

}}'

{ "_id": ObjectId("53b7f2383ed7755c2400002e"), "title": "Post Two", "author": "bob", "posted": ISODate("2014-07-05T12:40:24.0Z"), "pageViews": NumberInt(5), "comments": { "0": { "userid": "1", "text": "this is cool" }, "1": { "userid": "2", "text": "this is bad" }, "3": { "userid": "3", "text": "this is badexample" } "4": { "userid": "4", "text": "No Thanx" } } }