Question

I am developing a site in ruby on rails using mongoDB database. I am a beginner in mongoDB and I want to sort data using multiple keys. One of my collection is shown below.

dd_users
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004e"),   
   "name": "Ram",
   "score":5
    "created_at": ISODate("2011-10-17T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004f"),   
   "name": "Robert",
   "score":1
   "created_at": ISODate("2011-10-12T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004g"),   
   "name": "Molly Bracken",
   "score":3
   "created_at": ISODate("2011-10-15T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600005k"),   
   "name": "Ninou-Co France",
   "score":5
   "created_at": ISODate("2011-10-16T06: 31: 55.0Z"),
}

I want to sort the records in descending order of ‘score’ and ‘created_at’.
I used the mongomapper query as
1.DdUser.where({“name” => { “$ne” => nil}).sort([[“score”,”desc”],[“created_at”,”desc”]]). But am getting the result in the order of score only.

I am expecting the result

{
   "_id": ObjectId("4e9bcbdb1d41c866c600004e"),   
   "name": "Ram",
   "score":5
    "created_at": ISODate("2011-10-17T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600005k"),   
   "name": "Ninou-Co France",
   "score":5
   "created_at": ISODate("2011-10-16T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004g"),   
   "name": "Molly Bracken",
   "score":3
   "created_at": ISODate("2011-10-15T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004f"),   
   "name": "Robert",
   "score":1
   "created_at": ISODate("2011-10-12T06: 31: 55.0Z"),
}

Answer 1

DdUser.where("name" => { "$ne" => nil } ).sort(["score","desc"], ["created_at","desc"])