How count embedded document?

[Raitucarp]

I have a collection:

[
  {
    "title": "zaya",
    "text": "zaya",
    "_id": "50dd4993410d3b1804000001",
    "__v": 0,
    "time": "2012-12-28T07:26:11.999Z",
    "reports": [],
    "votes": []
  },
  {
    "title": "zaya",
    "text": "zaya",
    "_id": "50dd521749a49a5413000001",
    "__v": 0,
    "time": "2012-12-28T08:02:31.599Z",
    "reports": [],
    "votes": []
  },
  {
    "_id": "50dd494910aa935c0a000001",
    "title": "Barrbaba",
    "text": "yayaya",
    "aba": [
      {
        "position": "neutral",
        "name": "arara"
      },
      {
        "position": "pro",
        "name": "galaga"
      }
    ],
    "__v": 0,
    "time": "2012-12-28T07:24:57.853Z",
    "reports": [],
    "votes": []
  },
  {
    "title": "zaya",
    "text": "zaya",
    "_id": "50de8fbba01a01b812000001",
    "__v": 0,
    "time": "2012-12-29T06:37:47.607Z",
    "reports": [],
    "votes": [
      {
        "name": "arara",
        "vote": "up"
      },
      {
        "name": "yasama",
        "vote": "up"
      },
      {
        "name": "gangnam",
        "vote": "down"
      }
    ]
  }
]

How to count votes? In this case, only Id 50de8fbba01a01b812000001 has votes

[Raitucarp]

_id 50de8fbba01a01b812000001 has 3 votes, and how to do that with mongo?

[William Zola]

You can do this with the MongoDB aggregation framework.

Since it's not clear exactly what you want to count, or how you want the results displayed, I can't offer you example code.

 -William 

[Arthur Neves]

You could count using a simple map/reduce or use the aggregations framework to count as well. However if you want to count just to be able to query on them, you dont need to count, you can use the $size operator : http://docs.mongodb.org/manual/reference/operators/#_S_size 

something like this:

db.collection.find( { votes: { $size: 2 } } );