通过

$push

该 $push 运算符用于向文档中的数组添加指定值。 $push运算符将新元素添加到现有数组，而不会影响数组中的其他元素。

语法

db.collection.update({
    < query >
}, {
    $push: {
        < field >: < value >
    }
}, {
    < options >
})

参数

参数 说明
<query> 要更新的文档的选择条件。
<field> 将附加值的数组字段。
<value> 要附加到数组字段的值。
<options> 可选。 更新操作的附加选项。

例子

请考虑存储集合中的此示例文档。

{
    "_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 - 添加新的销售类别

若要将新的销售类别添加到 salesByCategory 数组，请使用字段上的 $push 运算符和具有类别名称及其销售量的新 Sales 对象运行查询。

db.stores.update(
   { _id: "0fcc0bf0-ed18-4ab8-b558-9848e18058f4" },
   { $push: { "sales.salesByCategory": { "categoryName": "Wine Accessories", "totalSales": 1000.00 } } }
)

此查询返回以下结果：

[
  {
    "acknowledged": true,
    "insertedId": null,
    "matchedCount": "1",
    "modifiedCount": "1",
    "upsertedCount": 0
  }
]

示例 2 - 将$push与$setWindowFields配合使用

若要检索“第一次启动顾问”公司下所有商店的不同销售量，请先运行查询以对公司内的商店进行分区。 然后，使用 $push 运算符创建从第一个到分区中的当前商店的销售列表。

db.stores.aggregate([{
        "$match": {
            "company": {
                "$in": ["First Up Consultants"]
            }
        }
    }, {
        "$setWindowFields": {
            "partitionBy": "$company",
            "sortBy": {
                "sales.totalSales": -1
            },
            "output": {
                "salesByStore": {
                    "$push": "$sales.totalSales",
                    "window": {
                        "documents": ["unbounded", "current"]
                    }
                }
            }
        }
    },
    {
        "$project": {
            "company": 1,
            "salesByStore": 1
        }
    }
])

此查询返回的前三个结果为：

[
    {
        "_id": "a0386810-b6f8-4b05-9d60-e536fb2b0026",
        "company": "First Up Consultants",
        "salesByStore": [
            327583
        ]
    },
    {
        "_id": "ad8af64a-d5bb-4162-9bb6-e5104126566d",
        "company": "First Up Consultants",
        "salesByStore": [
            327583,
            288582
        ]
    },
    {
        "_id": "39acb3aa-f350-41cb-9279-9e34c004415a",
        "company": "First Up Consultants",
        "salesByStore": [
            327583,
            288582,
            279183
        ]
    }
]

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