$not

The $not operator performs a logical NOT operation on a specified expression and selects documents that don't match the expression.

Syntax

{
    field: {
        $not: {
            < operator - expression >
        }
    }
}

Parameters

Parameter Description
operator-expression The expression to negate

Examples

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

{
    "_id": "0fcc0bf0-ed18-4ab8-b558-9848e18058f4",
    "name": "First Up Consultants | Beverage Shop - Satterfieldmouth",
    "location": {
        "lat": -89.2384,
        "lon": -46.4012
    },
    "staff": {
        "totalStaff": {
            "fullTime": 8,
            "partTime": 20
        }
    },
    "sales": {
        "totalSales": 75670,
        "salesByCategory": [
            {
                "categoryName": "Wine Accessories",
                "totalSales": 34440
            },
            {
                "categoryName": "Bitters",
                "totalSales": 39496
            },
            {
                "categoryName": "Rum",
                "totalSales": 1734
            }
        ]
    },
    "promotionEvents": [
        {
            "eventName": "Unbeatable Bargain Bash",
            "promotionalDates": {
                "startDate": {
                    "Year": 2024,
                    "Month": 6,
                    "Day": 23
                },
                "endDate": {
                    "Year": 2024,
                    "Month": 7,
                    "Day": 2
                }
            },
            "discounts": [
                {
                    "categoryName": "Whiskey",
                    "discountPercentage": 7
                },
                {
                    "categoryName": "Bitters",
                    "discountPercentage": 15
                },
                {
                    "categoryName": "Brandy",
                    "discountPercentage": 8
                },
                {
                    "categoryName": "Sports Drinks",
                    "discountPercentage": 22
                },
                {
                    "categoryName": "Vodka",
                    "discountPercentage": 19
                }
            ]
        },
        {
            "eventName": "Steal of a Deal Days",
            "promotionalDates": {
                "startDate": {
                    "Year": 2024,
                    "Month": 9,
                    "Day": 21
                },
                "endDate": {
                    "Year": 2024,
                    "Month": 9,
                    "Day": 29
                }
            },
            "discounts": [
                {
                    "categoryName": "Organic Wine",
                    "discountPercentage": 19
                },
                {
                    "categoryName": "White Wine",
                    "discountPercentage": 20
                },
                {
                    "categoryName": "Sparkling Wine",
                    "discountPercentage": 19
                },
                {
                    "categoryName": "Whiskey",
                    "discountPercentage": 17
                },
                {
                    "categoryName": "Vodka",
                    "discountPercentage": 23
                }
            ]
        }
    ]
}

Example 1: Use NOT operation as logical-query operator

The example helps to find stores where the number of full-time staff isn't equal to 5 using the $not operator with $eq. It returns only the name and staff fields for up to two such matching documents.

 db.stores.find({
     "staff.totalStaff.fullTime": {
         $not: {
             $eq: 5
         }
     }
 }, {
     "name": 1,
     "staff": 1
 }).limit(2)

The query returns up to two stores where full-time staff count differs from 5.

[
    {
        "_id": "a715ab0f-4c6e-4e9d-a812-f2fab11ce0b6",
        "name": "Lakeshore Retail | Holiday Supply Hub - Marvinfort",
        "staff": {
            "totalStaff": {
                "fullTime": 9,
                "partTime": 18
            }
        }
    },
    {
        "_id": "923d2228-6a28-4856-ac9d-77c39eaf1800",
        "name": "Lakeshore Retail | Home Decor Hub - Franciscoton",
        "staff": {
            "totalStaff": {
                "fullTime": 7,
                "partTime": 6
            }
        }
    }
]

Example 2: Use NOT operator as boolean-expression to identify stores that aren't high-volume

The example finds stores that don't have high sales volume (not greater than 50,000).

db.stores.aggregate([
  {
    $project: {
      name: 1,
      totalSales: "$sales.salesByCategory.totalSales",
      isNotHighVolume: {
        $not: { $gt: ["$sales.salesByCategory.totalSales", 50000] }
      },
      storeCategory: {
        $cond: [
          { $not: { $gt: ["$sales.salesByCategory.totalSales", 50000] } },
          "High Volume Store",
          "Small/Medium Store"
        ]
      }
    }
  },
  { $limit: 2 }
])

The query identifies stores that aren't high-volume.

 {
    "_id": "905d1939-e03a-413e-a9c4-221f74055aac",
    "name": "Trey Research | Home Office Depot - Lake Freeda",
    "totalSales": [ 37978 ],
    "isNotHighVolume": false,
    "storeCategory": "Small/Medium Store"
  },
  {
    "_id": "a715ab0f-4c6e-4e9d-a812-f2fab11ce0b6",
    "name": "Lakeshore Retail | Holiday Supply Hub - Marvinfort",
    "totalSales": [ 25731 ],
    "isNotHighVolume": false,
    "storeCategory": "Small/Medium Store"
  }

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