MongoDB - Using find() to get values in an array

Question

My collection contains documents of the following form:

        {
          'game_name': 'football',
          'scores': [4,1,2,7,6,0,5]
        }

How do I find the 'scores' of all such objects in the collection and sort them in ascending order?

Barno · Accepted Answer · 2014-08-04 07:43:31Z

1

If I understand your Question

db.yourcollection.aggregate([

{
    $unwind:"$scores"
},{

    $sort:{
        "scores":1
        }
},{    
        $group:{
            _id:null,
            scores:{$addToSet:"$scores"}
        }
},{

    $project:{
        _id:0,
        scores:1
    }
}

])

Result is:

{
    "result" : [ 
        {
            "scores" : [ 
                7, 
                5, 
                4, 
                6, 
                2, 
                1, 
                0
            ]
        }
    ],
    "ok" : 1
}

answered Aug 4, 2014 at 7:43

Barno

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2 Comments

xennygrimmato Over a year ago

Thanks a lot. Can you please explain $group and $project? I do not know what those are, and $unwind was new for me.

Barno Over a year ago

@Rayu sure ! My english is not perfect but i try to explain $unwind Create document for each element of array $group is similar Group of My Sql $project Reshapes a document, and you can decide witch element do you want see, rename and others function like $toLower or $toUpper etc... doc aggregation

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