$not (boolean expression)

APPLIES TO: MongoDB vCore

The $not operator returns the opposite boolean value of the expression. It performs a logical NOT operation on a single expression. If the expression evaluates to true, $not returns false. If the expression evaluates to false, $not returns true. This operator is useful for negating conditions and finding documents that don't meet specific criteria.

Syntax

The syntax for the $not operator is as follows:

{
  $not: <expression>
}

Parameters

Description
<expression> A single expression to be negated. The $not operator returns the logical opposite of this expression's boolean value.

Example

Example 1: 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", 20000] }
      },
      storeCategory: {
        $cond: [
          { $not: { $gt: ["$sales.salesByCategory.totalSales", 20000] } },
          "Small-Medium Store",
          "High Volume Store"
        ]
      }
    }
  },
  { $limit: 2 }
])

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

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

Example 2: Validate stores without understaffing issues

The example identifies stores that don't have understaffing issues (not fewer than 10 total staff members).

db.stores.aggregate([
  { $match: {"_id": "e6895a31-a5cd-4103-8889-3b95a864e5a6"} },
  {
    $project: {
      name: 1,
      totalStaff: { $add: ["$staff.employeeCount.fullTime", "$staff.employeeCount.partTime"] },
      isNotUnderstaffed: {
        $not: { $lt: [{ $add: ["$staff.employeeCount.fullTime", "$staff.employeeCount.partTime"] }, 10] }
      },
      staffingStatus: {
        $cond: [
          { $not: { $lt: [{ $add: ["$staff.employeeCount.fullTime", "$staff.employeeCount.partTime"] }, 10] } },
          "Adequately Staffed",
          "Understaffed"
        ]
      }
    }
  }
])

The query determines if the store isn't understaffed.

{
  "_id": "e6895a31-a5cd-4103-8889-3b95a864e5a6",
  "name": "VanArsdel, Ltd. | Picture Frame Store - Port Clevelandton",
  "totalStaff": 14,
  "isNotUnderstaffed": true,
  "staffingStatus": "Adequately Staffed"
}

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