Group array after unwind and match

Question

I have a twice nested schema:

mongoose.model('Team', mongoose.Schema(
{
 players : [{ 
    trikots : [{
        isNew : Boolean,
        color : String
    }]
 }]
})

For now, my query looks like this:

Team.aggregate()
        .match({'_id' : new ObjectId(teamId)})
        .unwind('players')
        .unwind('players.trikots')
        .match({'players.trikots.isNew' : 'red', 'players.trikots.isNew' : true})
        .exec(sendBack);

But I would like to have one Team object, that contains all players as an array. How can I achieve that?

thegreenogre · Accepted Answer · 2015-05-08T09:16:06.300

18

Use Group on _id with $push operator to return all players into an array.

Team.aggregate()
        .match({'_id' : new ObjectId(teamId)})
        .unwind('players')
        .unwind('players.trikots')
        .match({'players.trikots.color' : 'red', 'players.trikots.isNew' : true})
        .group({'_id':'$_id','players': {'$push': '$players'}})
        .exec(sendBack);

If you want any other field to be included in the final doucment add it to _id field during group operation.

.group({'_id':{'_id':'$_id','some_other_field':'$some_other_field'},'players': {'$push': '$players'}})

edited May 08 '15 at 09:16

answered May 08 '15 at 08:56

thegreenogre

1,559
11
22

Error: "the group aggregate field 'id' must be defined as an expression inside an object" – Florian Mozart May 08 '15 at 09:03
Oh sorry, my bad it should be `_id` not `id`. – thegreenogre May 08 '15 at 09:04
If you want any other field from your original team object just add it to the `_id` in group stage. I am not sure what other field you are missing, Can you edit your question to include the output document you want? – thegreenogre May 08 '15 at 09:14
Nice answer. Is there a way to also get the matching element as well? – Justin Jan 19 '16 at 18:46
@Justin have a look at [this answer](http://stackoverflow.com/a/29072062/2745704). – thegreenogre Jan 20 '16 at 06:27

Group array after unwind and match

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