mongodb用子文档做为查询条件的两种方法

    {
      "_id": ObjectId("52fc6617e97feebe05000000"),
      "age": 28,
      "level": NumberInt(500),
      "name": "name5",
      "person": [
        {
          "level": 5,
          "score": 100,
        "ccc":{"ccc3":56,"fff3":78}
        },
        {
          "level": 7,
          "score": 90,
          "like": "music"
        }
      ],
      "score": NumberInt(500),
      "sex": "男"
    }

db.testColl.find({"person.level":7});

db.testColl.find({"person.ccc.ccc3":56});

db.testColl.find({"person":{"$elemMatch":{"level":5}}});

db.testColl.find({"person":{"$elemMatch":{"ccc":{"$elemMatch":{"ccc3":56}}}}});

db.testColl.find({"person":{"$elemMatch":{"ccc":{"ccc3":56,"fff3":78}}}});

db.testColl.find({"person":{"$elemMatch":{"ccc.ccc3":56}}});