如何通过嵌入文档中的字段来订购mongoDB查询？

Question

I have these documents in a mongoDB:

    /* 1 */
{
    "_id" : ObjectId("553ce99a39108e2b7c1edeb9"),
    "coleccion" : "aplicaciones",
    "nombre" : "Mascotas",
    "descripcion" : "Censo de mascotas",
    "tipo" : "privada"
}

/* 2 */
{
    "_id" : ObjectId("553e316e39108e802a1edeb9"),
    "coleccion" : "aplicaciones",
    "nombre" : "otra aplicacionn",
    "descripcion" : "w aplicacion",
    "tipo" : "privada",
    "campoId" : [ 
        {
            "id" : "1430145364",
            "id_campo" : "553bffca39108eb163cff7aa",
            "orden" : 90
        }, 
        {
            "id" : "1430145368",
            "id_campo" : "553bffed39108e346ccff7ab",
            "orden" : 100,
            "estado" : "0"
        }, 
        {
            "id" : "1430145370",
            "id_campo" : "553c001139108ebc63cff7aa",
            "orden" : 29,
            "estado" : "1"
        }, 
        {
            "id" : "1430145395",
            "id_campo" : "553c001139108ebc63cff7aa",
            "orden" : 9,
            "estado" : "0"
        }
    ]
}

I need to query and sort the data in ascending order of each document using the field " campoId.orden " and have executed this query:

db.getCollection('aplicaciones').find({}).sort({'campoId.orden' : -1})

but I do not get the order I want. can anyone suggest me a way?

Answer 1

In your documents orden in nested array, so you should use mongo aggregation. So below step will follow :

1> First check campoId exits or not $exists

2> Then unwind campoId array $unwind

3> Then group all fields $group

So query as below :

db.aplicaciones.aggregate({
    "$match": {
      "campoId": {
        "$exists": true // check here campoId presents or not using exists
      }
    }
  }, {
    "$unwind": "$campoId" // unwind campoId array 
  }, {
    "$sort": {
      "campoId.orden": -1
    }
  },
  //groups all fields
  {
    "$group": {
      "_id": "$_id",
      "coleccion": {
        "$first": "$coleccion"
      },
      "nombre": {
        "$first": "$nombre"
      },
      "descripcion": {
        "$first": "$descripcion"
      },
      "tipo": {
        "$first": "$tipo"
      },
      "campoId": {
        "$push": "$campoId"
      }
    }
  }).pretty()