$pullAll (array update)

APPLIES TO: MongoDB vCore

The $pullAll operator is used to remove all instances of the specified values from an array. This operator is useful when you need to clean up arrays by removing multiple specific elements in a single operation.

Both $pull and $pullAll are used to remove elements from an array, but they differ in how they identify the elements to be removed. $pull removes all elements from an array that match a specific condition, which can be a simple value or a more complex query (like matching sub-document fields). On the other hand, $pullAll removes specific values provided as an array of exact matches, but it doesn't support conditions or queries. Essentially, $pull is more flexible as it allows conditional removal based on various criteria, while $pullAll is simpler, working only with a fixed set of values.

The syntax for the $pullAll operator is as follows:

{
  $pullAll: { <field1>: [ <value1>, <value2>, ... ], ... }
}

Let's understand the usage with the following sample json.

{
  "_id": "7954bd5c-9ac2-4c10-bb7a-2b79bd0963c5",
   "name": "Lakeshore Retail | DJ Equipment Stop - Port Cecile",
  "location": {
    "lat": 60.1441,
    "lon": -141.5012
  },
  "staff": {
    "totalStaff": {
      "fullTime": 2,
      "partTime": 0
    }
  },
  "sales": {
    "salesByCategory": [
      {
        "categoryName": "DJ Headphones",
        "totalSales": 35921
      }
    ],
    "fullSales": 3700
  },
  "promotionEvents": [
    {
      "eventName": "Bargain Blitz Days",
      "promotionalDates": {
        "startDate": {
          "Year": 2024,
          "Month": 3,
          "Day": 11
        },
        "endDate": {
          "Year": 2024,
          "Month": 2,
          "Day": 18
        }
      },
      "discounts": [
        {
          "categoryName": "DJ Turntables",
          "discountPercentage": 18
        },
        {
          "categoryName": "DJ Mixers",
          "discountPercentage": 15
        }
      ]
    }
  ],
  "tag": [
    "#ShopLocal",
    "#SeasonalSale",
    "#FreeShipping",
    "#MembershipDeals"
  ]
}

To remove the discounts for "#MembershipDeals" and "#SeasonalSale" from the 'tag' array.

db.stores.updateMany(
    //filter
    { "_id": "7954bd5c-9ac2-4c10-bb7a-2b79bd0963c5"},
    {
      $pullAll: {
        "tag": ["#MembershipDeals","#SeasonalSale" ]
      }
    }
)

This query would return the following document.

{
  "acknowledged": true,
  "insertedId": null,
  "matchedCount": 1,
  "modifiedCount": 1,
  "upsertedCount": 0
}

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