I'm trying to obtain an object like this from my mongodb, counting the OS per month:

`{January: {Android: 30, iOS: 10, winPhone: 5}, February: {Android: 4, iOS: 40}, etc}.` 

And here is my mongoose schema: 

```
var MySchema = new Schema({
  date: {type: Date,  default: Date.now},
  os: String
});

```

Can give me someone an idea? Is there a way to create a single query to return me the entire object or should I build it piece by piece, unifying multiple queries?

Thank you!