$sortArray (array expression)

APPLIES TO: MongoDB vCore

The $sortArray operator is used to sort the elements of an array. This operator can be particularly useful when you need to sort arrays within your documents based on specific fields or criteria. It can be applied to arrays of embedded documents or simple arrays of values.

Syntax

The syntax for the $sortArray operator is as follows:

{
  $sortArray: {
    input: <arrayExpression>,
    sortBy: <sortSpecification>
  }
}

Parameters

	Description
input	The array to be sorted.
sortBy	Specifies the sort order. This can be a single field or multiple fields with their corresponding sort order (1 for ascending, -1 for descending).

Example

Let's understand the usage with sample json from stores dataset.

{
  "_id": "d3c9df51-41bd-4b4e-a26b-b038d9cf8b45",
  "location": {
    "lat": -67.7571,
    "lon": 97.2505
  },
  "sales": {
    "totalSales": 149849,
    "salesByCategory": [
      {
        "categoryName": "DJ Speakers",
        "totalSales": 36972
      },
      {
        "categoryName": "DJ Headphones",
        "totalSales": 12877
      },
      {
        "categoryName": "Music Accessories",
        "totalSales": 40000
      },
      {
        "categoryName": "DJ Accessories",
        "totalSales": 60000
      }
    ]
  },
  "tag": [
    "#ShopLocal",
    "#FashionStore",
    "#SeasonalSale",
    "#FreeShipping",
    "#MembershipDeals"
  ]
}

Example 1: Sorting an Array of Embedded Documents

The example query sorts the sales.salesByCategory array within each document in descending order based on totalSales.

db.stores.aggregate([
  {$match: {"_id": "d3c9df51-41bd-4b4e-a26b-b038d9cf8b45"} }
, {
    $project: {
      sortedSalesByCategory: {
        $sortArray: {
          input: "$sales.salesByCategory",
          sortBy: { totalSales: -1 }
        }
      }
    }
  }
])

The query returns array elements sorted by totalSales for the sample json.

{
  "_id": "d3c9df51-41bd-4b4e-a26b-b038d9cf8b45",
  "sortedSalesByCategory": [
    { "categoryName": "DJ Accessories", "totalSales": 60000 },
    { "categoryName": "Music Accessories", "totalSales": 40000 },
    { "categoryName": "DJ Speakers", "totalSales": 36972 },
    { "categoryName": "DJ Headphones", "totalSales": 12877 }
  ]
}

Related content

- Review options for Migrating from MongoDB to Azure Cosmos DB for MongoDB (vCore) - Read more about Feature compatibility with MongoDB.