$sum - Amazon DocumentDB
Example (MongoDB Shell)Code examples
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$sum

The $sum operator in Amazon DocumentDB returns the sum of the specified expression for each document in a group. It is a group accumulator operator that is typically used in the $group stage of an aggregation pipeline to perform summation calculations.

Parameters

  • expression: The numeric expression to sum. This can be a field path, an expression, or a constant.

Example (MongoDB Shell)

The following example demonstrates the use of the $sum operator to calculate the total sales for each product.

Create sample documents

db.sales.insertMany([
  { product: "abc", price: 10, quantity: 2 },
  { product: "abc", price: 10, quantity: 3 },
  { product: "xyz", price: 20, quantity: 1 },
  { product: "xyz", price: 20, quantity: 5 }
]);

Query example

db.sales.aggregate([
  { $group: {
      _id: "$product",
      totalSales: { $sum: { $multiply: [ "$price", "$quantity" ] } }
    }}
]);

Output

[
  { "_id": "abc", "totalSales": 50 },
  { "_id": "xyz", "totalSales": 120 }
]

Code examples

To view a code example for using the $sum command, choose the tab for the language that you want to use:

Node.js
const { MongoClient } = require('mongodb');

async function example() {
  const uri = 'mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false';
  const client = new MongoClient(uri);

  try {
    await client.connect();

    const db = client.db('test');
    const collection = db.collection('sales');

    const result = await collection.aggregate([
      { $group: {
          _id: "$product",
          totalSales: { $sum: { $multiply: [ "$price", "$quantity" ] } }
        }}
    ]).toArray();

    console.log(result);

  } catch (error) {
    console.error('Error:', error);
  } finally {
    await client.close();
  }
}

example();
Python
from pymongo import MongoClient
from pprint import pprint

def example():
    client = None
    try:
        client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')

        db = client.test
        collection = db.sales

        result = list(collection.aggregate([
            { '$group': {
                '_id': '$product',
                'totalSales': { '$sum': { '$multiply': [ '$price', '$quantity' ] } }
            }}
        ]))

        pprint(result)

    except Exception as e:
        print(f"An error occurred: {e}")

    finally:
        if client:
            client.close()

example()