sorting - Sort Sub Documents in MongoDB

Question

Is there a way to sort sub documents in a mongo query?

For example:

{
  "_id" : ObjectId("4c69d19532f73ad544000001"),
  "content" : "blah blah blah",
  "comments" : [
    {"author": "jim", "content":"comment content 1", "date" : "07-24-1995"},
    {"author": "joe", "content":"comment content 2", "date" : "07-24-1996"},
    {"author": "amy", "content":"comment content 3", "date" : "09-10-1999"}
  ]
}
{
  "_id" : ObjectId("4c69d19532f73ad544000002"),
  "content" : "blah blah blah",
  "comments" : [
    {"author": "jim", "content":"comment content 1", "date" : "07-24-1995"},
    {"author": "joe", "content":"comment content 2", "date" : "07-24-1996"},
    {"author": "amy", "content":"comment content 3", "date" : "07-24-1997"}
  ]
}

I want these documents to be ordered in however way I decide and then have comments ordered within my a document by reverse order of date or any other sorting I want.

Is that possible with mongoDB?

Answer 1

In mongo version 2.4 or above, you can use $sort while updating. The new modifier let you sort sub document.

More information could read this page, http://docs.mongodb.org/manual/reference/operator/sort/