MongoDb sum query

Question

For example, I have the following document in MongoDB:

{ "_id" : ObjectId("524091f99c49c4c3f66b0e46"), "hour" : 10, "incoming", 100}

{ "_id" : ObjectId("5240a045dbeff33c7333aa51"), "hour" : 11, "incoming", 200}

{ "_id" : ObjectId("5240a2ecda0d37f35c618aca"), "hour" : 12, "incoming", 300}

From the above document database, I want to query "SUM the number of incoming between 11 - 12" 

the output should be 500, how can I perform that using Mongo Shell?

Answer 1

 The solution to your problem is the aggregation framework that mongodb provides. Here's what your query would look like:

db.CollectionNameGoesHere.aggregate({ $match: {

    $and: [

        { hour: { $gte: 11 } },

        { hour: { $lte: 12 } }

    ]

} },

{ $group: { _id : null, sum : { $sum: "$incoming" } } });

You can also shape the resulting document to only contain the sum by adding a $project operator at the end of the pipeline, like so:

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

If you want more information regarding the same kindly refer to the following mongodb tutorial 

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