Question 118479 in Mongodb Question posted in
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MongoDB – Get the sum of an object in an array

Hi I’m very new to MongoDB, I’m trying to get the total price and promo of the below MongoDB data with document.collection.find and $add functionality:

Data:

[
  {
    "catalog":"A",
    "book":[
    {
      "title":"Mermaid yang terdampar",
      "price":90000,
      "promo":15000
    },
    {
      "title":"Srigala berbulu domba",
      "price":30000,
      "promo":15000
    }
  }
]

And my expected result would be sth like this:

[
  {
    "catalog": "A",
    "totalPrice": 140000,
    "totalPromo": 32000
  },
]

Does anybody ever encounter a similar issue? I’m confused with the query 🙂

Tags:

3

Answers


  1. 0

    use aggregate

    db.getCollection('myCollection').aggregate([
    { "$group": {
        "_id": "$tempId",
        "totalPrice": { 
            "$sum": { "$sum": "$book.price" } 
        },
        "totalPromo": { 
            "$sum": { "$sum": "$book.promo" } 
        }
    } }
])
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  2. 0

    For .find() query, you can direct use the $sum operator.

    db.collection.find({},
{
  catalog: 1,
  totalSum: {
    $sum: "$book.price"
  },
  totalPromo: {
    $sum: "$book.promo"
  }
})

    Sample Mongo Playground

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  3. 0

    Using $group (aggregation)

    db.getCollection('catlog').aggregate([{ 
    $group: {
        _id: "$_id",
        catalog: { $first: "$catalog" },
        totalPrice: { "$sum": { $sum: "$book.price" } },
        totalPromo: { "$sum": { $sum: "$book.promo" } }
    }
}])

    Output will be:

    {
    "_id" : ObjectId("6247b33cffc5b6f714769fbb"),
    "catalog" : "A",
    "totalPrice" : 120000,
    "totalPromo" : 30000
}
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