$pow (as arithmetic expression operator) usage on Azure Cosmos DB for MongoDB (vCore)

  • 04/11/2025

The $pow operator is used to raise a number to a specified exponent. This can be useful in various scenarios where mathematical computations are required within your documents.

Syntax

{ $pow: [ <number>, <exponent> ] }

Parameters

Description
<number> The base number to be raised to the exponent.
<exponent> The exponent to raise the base number to.

Example(s)

Example 1: Calculate the square of a number

Suppose you want to calculate the square of the fullSales field in the sales document.

db.collection.aggregate([
  {
    $project: {
      fullSalesSquare: { $pow: [ "$sales.fullSales", 2 ] }
    }
  }
])

This output shows that the fullSalesSquare field contains the square of fullSales.

[
  { "_id": 1, "sales": { "fullSales": 10 }, "fullSalesSquare": 100 },
  { "_id": 2, "sales": { "fullSales": 20 }, "fullSalesSquare": 400 },
  { "_id": 3, "sales": { "fullSales": 30 }, "fullSalesSquare": 900 }
]

Example 2: Calculate a power of a specific category's total sales

If you want to calculate totalSales raised to the power of 3 for the "DJ Headphones" category:

db.collection.aggregate([
  {
    $unwind: "$sales.salesByCategory"
  },
  {
    $match: { "sales.salesByCategory.categoryName": "DJ Headphones" }
  },
  {
    $project: {
      totalSalesCubed: { $pow: [ "$sales.salesByCategory.totalSales", 3 ] }
    }
  }
])

This output shows the totalSales value raised to the power of 3 for the "DJ Headphones" category:

[
  {
    "_id": 4,
    "category": "DJ Headphones",
    "sales": { "salesByCategory": { "totalSales": 5 } },
    "totalSalesCubed": 125
  },
  {
    "_id": 5,
    "category": "DJ Headphones",
    "sales": { "salesByCategory": { "totalSales": 10 } },
    "totalSalesCubed": 1000
  }
]

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