mongodb如何查询带key的二维数组

如题，要检索links下的url=100218的记录，目前用"links.url":100218 或elematch都下行。
links因为历史原因数组带有key，暂时不能去，哪位知道在这种带key的情况下如何检索？不胜感激！
"content": "回复[3864968030]：对[1733199938]的评论：哈哈哈哈",
"links": {
    "[1733199938]": {
      "url": "\/zuoye\/51b83ca9817473fd51000850?fid=15#15",
      "text": "15楼",
      "title": "",
      "target": "_self",
      "type": NumberLong(7)
    },
    "[3864968030]": {
      "url": NumberLong(100218),
      "text": "拉风的车",
      "title": "拉风的车",
      "target": "_self",
      "type": NumberLong(0)
    }
  }
              
               
               

            Stackoverlow网站上面也有这个问题，看来你不得不去掉key了，参考：
http://stackoverflow.com/questions/8901977/mongodb-nested-array-search
Wildcard queries are not possible with MongoDB, so with the given document structure, the key (0,1,2, etcetera) of the sub-document must be known. For instance, the following query will work:
> db.test.find({"visits.2.payment":{$lt:35}})
However,
> db.test.find({"visits.payment":{$lt:35}})
Will not work in this case, and
> db.test.find({"visits.*.payment":{$lt:35}})
will also not return any results.