$sqrt

  • 04/11/2025

The $sqrt operator is used to return the square root of a specified number. It is commonly used in aggregation pipelines to perform mathematical calculations on numeric fields within documents.

Syntax

{ $sqrt: <expression> }

Parameters

Parameter Description
<expression> Any valid expression that resolves to a number.

Example(s)

Example 1: Calculate the square root of a specific sales value

The following example demonstrates how to calculate the square root of the fullSales value within a document.

db.collection.aggregate([
  {
    $project: {
      name: 1,
      fullSales: 1,
      sqrtFullSales: { $sqrt: "$sales.fullSales" }
    }
  }
])

This output includes the original fullSales value and its square root:

[
  { "_id": 1, "name": "Store A", "sales": { "fullSales": 100 }, "sqrtFullSales": 10 },
  { "_id": 2, "name": "Store B", "sales": { "fullSales": 225 }, "sqrtFullSales": 15 },
  { "_id": 3, "name": "Store C", "sales": { "fullSales": 400 }, "sqrtFullSales": 20 }
]

Example 2: Calculate the square root of total sales by category

This example shows how to calculate the square root of the totalSales for each sales category.

db.collection.aggregate([
  {
    $unwind: "$sales.salesByCategory"
  },
  {
    $project: {
      name: 1,
      categoryName: "$sales.salesByCategory.categoryName",
      totalSales: "$sales.salesByCategory.totalSales",
      sqrtTotalSales: { $sqrt: "$sales.salesByCategory.totalSales" }
    }
  }
])

This output calculates the square root of the totalSales for each sales category:

[
  {
    "_id": 4,
    "name": "Electronics Store",
    "categoryName": "Laptops",
    "totalSales": 144,
    "sqrtTotalSales": 12
  },
  {
    "_id": 5,
    "name": "Fashion Outlet",
    "categoryName": "Shoes",
    "totalSales": 81,
    "sqrtTotalSales": 9
  }
]

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