MongoDb sum query

Question

For example I have the following data in MongoDB:

{ "_id" : ObjectId("524091f99c49c4c3f66b0e46"), "hour" : 10, "incoming", 100} { "_id" : ObjectId("5240a045dbeff33c7333aa51"), "hour" : 11, "incoming", 200} { "_id" : ObjectId("5240a2ecda0d37f35c618aca"), "hour" : 12, "incoming", 300} 

Now I want to query "SUM the number of incoming between 11 - 12" (the result should be 500), how could I do this using Mongo Shell?

Answer 1

As llovet suggested, the aggregation framework is the way to go. 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 } } 

Answer 2

Some examples if you use mongoose:

1. Calculate total sum of product prices :

Products.aggregate([ { $match: {} }, { $group:   { _id : null, sum : { $sum: "$Price" } } }]) .then(res => console.log(res[0].sum)); 

( { $match: {} }, can be removed. )

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2. Sum of Product's prices in each category:

Products.aggregate([{ $group:   { _id : '$Category', sum : { $sum: "$Price" } } }]) .then(res => console.log(res));