$dateAdd

運算子會將 $dateAdd 指定的時間單位數目新增至日期。 在您需要根據指定日期和時間間隔計算未來日期的案例中，這非常有用。

語法

$dateAdd: {
   startDate: <expression>,
   unit: <string>,
   amount: <number>,
   timezone: <string>  // Optional
}

參數

範例

請參考商店集合中的此範例檔。

{
    "_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
                }
            ]
        }
    ]
}

範例 1：將天數新增至日期

此查詢會透過將 7 天新增至從巢狀年、月和日欄位建構的日期來投影 eventName 和計算 a newEndDate 。 結果是一份簡化的檔，其中顯示事件名稱和其延伸結束日期。

db.stores.aggregate([
  { $match: { _id: "e6410bb3-843d-4fa6-8c70-7472925f6d0a" } },
  { $unwind: "$promotionEvents" },
  { $unwind: "$promotionEvents.promotionalDates" },
  {
    $project: {
      eventName: 1,
      newEndDate: {
        $dateAdd: {
          startDate: {
            $dateFromParts: {
              year: "$promotionEvents.promotionalDates.endDate.Year",
              month: "$promotionEvents.promotionalDates.endDate.Month",
              day: "$promotionEvents.promotionalDates.endDate.Day"
            }
          },
          unit: "day",
          amount: 7
        }
      }
    }
  }
])

此查詢會傳回下列結果。

[
   {
     "_id": "e6410bb3-843d-4fa6-8c70-7472925f6d0a",
     "newEndDate": "2024-10-06T00:00:00.000Z"
   }
]

範例 2：將月份新增至日期

此彙總查詢會投影 ， eventName 並計算 newStartDate，方法是將 1 個月新增至巢狀升級欄位的重建開始日期。 這有助於根據原始排程來判斷調整的事件開始日期。 此查詢會從巢狀促銷事件資料傳回每個文件的 eventName 和原始 startDate 後 1 個月的 newStartDate。

db.stores.aggregate([
  { $match: { _id: "e6410bb3-843d-4fa6-8c70-7472925f6d0a" } },
  { $unwind: "$promotionEvents" },
  { $unwind: "$promotionEvents.promotionalDates" },
  {
    $project: {
      eventName: "$promotionEvents.eventName",
      newStartDate: {
        $dateAdd: {
          startDate: {
            $dateFromParts: {
              year: "$promotionEvents.promotionalDates.startDate.Year",
              month: "$promotionEvents.promotionalDates.startDate.Month",
              day: "$promotionEvents.promotionalDates.startDate.Day"
            }
          },
          unit: "month",
          amount: 1
        }
      }
    }
  }
])

此查詢會傳回下列結果。

[
   {
     "_id": "e6410bb3-843d-4fa6-8c70-7472925f6d0a",
     "eventName": "Massive Markdown Mania",
     "newStartDate": "2024-10-21T00:00:00.000Z"
   }
]

相關內容

• 檢視從 MongoDB 遷移到 Azure DocumentDB 的選項。
• 閱讀有關 與 MongoDB 的功能相容性的更多資訊。