Group result by 15 minutes time interval in MongoDb

Question

I have a \"status\" collection like this strcture -

{
    _id: ObjectId(\"545a0b63b03dbcd1238b4567\"),
    status: 1004,
    comment: \"Rem dolor ipsam place         


        

Answer 1

A little more beautiful for mongo db.version() < 3.0

db.collection.aggregate([
    {$match: {created_at:{$exists:1}}},
    {$group: {
        _id: {$add:[
            {$dayOfYear: "$created_at" },
            {$multiply: [{$year: "$created_at"}, 1000]}
        ]},
        count: {$sum: 1 }
    }},
    {$sort:{_id:-1}}
])