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db.command.aggregate.multiply

1. Operator Description​

Function: Returns the product of the input numeric parameters.

Declaration: db.command.aggregate.multiply([expression1, expression2, ...])

2. Operator Parameters​

FieldTypeRequiredDescription
-ExpressionRequiredThe parameter can be any expression that resolves to a number.

3. Sample Code​

Suppose the collection fruits contains the following records:

{ "_id": 1, "name": "apple", "price": 10, "quantity": 100 }
{ "_id": 2, "name": "orange", "price": 15, "quantity": 50 }
{ "_id": 3, "name": "lemon", "price": 5, "quantity": 20 }

Calculate the total value of each fruit:

// Sample code in the Cloud Function environment
const tcb = require('@cloudbase/node-sdk')
const app = tcb.init({
  env: 'xxx'
})

const db = app.database()
const $ = db.command.aggregate
const _ = db.command

exports.main = async (event, context) => {
  const res = await db
    .collection('fruits')
    .aggregate()
    .project({
      name: 1,
      total: $.multiply(['$price', '$quantity'])
    })
    .end()
  console.log(res.data)
}

The returned result is as follows:

{ "_id": 1, "name": "apple", "total": 1000 }
{ "_id": 2, "name": "orange", "total": 750 }
{ "_id": 3, "name": "lemo", "total": 100 }