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$month

Extracts the month portion from a date value, returning a number between 1 and 12, where 1 represents January and 12 represents December. This operator is essential for seasonal analysis and monthly reporting.

Syntax

$month: <dateExpression>

Parameters

dateExpressionobjectrequired

An expression that resolves to a Date, a Timestamp, or an ObjectId. If the expression resolves to null or is missing, $month returns null.

Examples

Extract month from store opening date

This query extracts the month portion from the store opening date to analyze seasonal opening patterns.

Query:

db.stores.aggregate([
  { $match: {_id: "905d1939-e03a-413e-a9c4-221f74055aac"} },
  {
    $project: {
      name: 1,
      storeOpeningDate: 1,
      openingMonth: {
        $month: "$storeOpeningDate"
      },
      openingMonthName: {
        $switch: {
          branches: [
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 1] }, then: "January" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 2] }, then: "February" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 3] }, then: "March" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 4] }, then: "April" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 5] }, then: "May" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 6] }, then: "June" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 7] }, then: "July" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 8] }, then: "August" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 9] }, then: "September" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 10] }, then: "October" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 11] }, then: "November" },
            { case: { $eq: [{ $month: "$storeOpeningDate" }, 12] }, then: "December" }
          ]
        }
      }
    }
  }
])

Output:

[
  {
    "_id": "905d1939-e03a-413e-a9c4-221f74055aac",
    "name": "Trey Research | Home Office Depot - Lake Freeda",
    "storeOpeningDate": "2024-12-30T22:55:25.779Z",
    "openingMonth": 12,
    "openingMonthName": "December"
  }
]

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