$hour

运算符 $hour 将日期的小时部分作为介于 0 和 23 之间的数字返回。 运算符接受解析为 Date、Timestamp 或 ObjectId 的日期表达式。

Syntax

{
  $hour: <dateExpression>
}

参数

例子

请考虑商店集合中的这个示例文档。

{
    "_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
                }
            ]
        }
    ]
}

示例 1：从当前日期提取小时

此查询从当前日期和时间中提取 hour 数据。

db.stores.aggregate([
  { $match: { "_id": "e6410bb3-843d-4fa6-8c70-7472925f6d0a" } },
  {
    $project: {
      name: 1,
      storeOpeningDate: 1,
      currentHour: { $hour: new Date() },
      documentHour: { $hour: "$storeOpeningDate" }
    }
  }
])

此查询返回以下结果。

[
  {
    "_id": "e6410bb3-843d-4fa6-8c70-7472925f6d0a",
    "name": "Relecloud | Toy Collection - North Jaylan",
    "storeOpeningDate": "2024-09-05T11:50:06.549Z",
    "currentHour": 12,
    "documentHour": 11
  }
]

相关内容

• 查看有关 从 MongoDB 迁移到适用于 MongoDB 的 Azure Cosmos DB (vCore) 的选项。
• 详细了解 与 MongoDB 的功能兼容性。