i am trying to sort a simple array of objects but i am struggling with it. I read several post about how to do it and many of them recomend $unwind the array then $sort and then $group... but it is not working for me because after group i lose the "name" porpertie

Here is my document:

{
        "_id" : 1,
        "name" : "Aurelia Menendez",
        "scores" : [
                {
                        "type" : "exam",
                        "score" : 60.06045071030959
                },
                {
                        "type" : "quiz",
                        "score" : 52.79790691903873
                },
                {
                        "type" : "homework",
                        "score" : 71.76133439165544
                },
                {
                        "type" : "homework",
                        "score" : 34.85718117893772
                }
        ]
}

I am trying this

{ $unwind: '$scores' },
{ $sort: { 'score': 1 } },
{
    $group: {
        _id: '$_id',
        scores: { $push: '$scores' }
    }
}

Expected output

{
        "_id" : 1,
        "name" : "Aurelia Menendez",
        "scores" : [
                {
                        "type" : "homework",
                        "score" : 71.76133439165544
                },
                {
                        "type" : "exam",
                        "score" : 60.06045071030959
                },
                {
                        "type" : "quiz",
                        "score" : 52.79790691903873
                },
            
                {
                        "type" : "homework",
                        "score" : 34.85718117893772
                }
        ]
}

CodePudding user response：

Query

• your query with small changes and with the $first extra accumulator
• all ids will have the same name, because they belonged to the first 1 document before the unwind, so we just take one (the first)

Test code here

aggregate(
[{"$unwind": {"path": "$scores"}},
 {"$sort": {"scores.score": -1}},
 {"$group": 
   {"_id": "$_id",
    "name": {"$first": "$name"},
    "scores": {"$push": "$scores"}}}])