运算符 $addToSet
将元素添加到数组(如果它们尚不存在),同时确保集内元素的唯一性。
{
$addToSet: { <field1>: <value1>, ... }
}
参数 | 说明 |
---|---|
<field1> |
要向其中添加元素的字段。 |
<value1> |
要添加至数组中的值。 |
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
}
]
}
]
}
若要向标记数组添加新标记,请使用 $addToSet 运算符运行查询以添加新值。
db.stores.update({
"_id": "7954bd5c-9ac2-4c10-bb7a-2b79bd0963c5"
}, {
"$addToSet": {
"tag": "#ShopLocal"
}
})
此查询返回以下结果:
[
{
"acknowledged": true,
"insertedId": null,
"matchedCount": "1",
"modifiedCount": "0",
"upsertedCount": 0
}
]
若要向数组添加新事件 promotionEvents
,请使用$addToSet运算符和要添加的新提升对象运行查询。
db.stores.update({
"_id": "7954bd5c-9ac2-4c10-bb7a-2b79bd0963c5"
}, {
"$addToSet": {
"promotionEvents": {
"eventName": "Summer Sale",
"promotionalDates": {
"startDate": {
"Year": 2024,
"Month": 6,
"Day": 1
},
"endDate": {
"Year": 2024,
"Month": 6,
"Day": 15
}
},
"discounts": [{
"categoryName": "DJ Speakers",
"discountPercentage": 20
}]
}
}
})
此查询返回以下结果:
[
{
"acknowledged": true,
"insertedId": null,
"matchedCount": "1",
"modifiedCount": "1",
"upsertedCount": 0
}
]
若要检索“第一次启动顾问”公司内每个商店的城市列表,请运行对公司第一个分区商店的查询。 然后,使用 $addToSet 运算符为分区中的每个商店添加不同的城市。
db.stores.aggregate([{
"$match": {
"company": {
"$in": ["First Up Consultants"]
}
}
}, {
"$setWindowFields": {
"partitionBy": "$company",
"sortBy": {
"sales.totalSales": -1
},
"output": {
"citiesForCompany": {
"$push": "$city",
"window": {
"documents": ["unbounded", "current"]
}
}
}
}
}, {
"$project": {
"company": 1,
"name": 1,
"citiesForCompany": 1
}
}])
此查询返回的前两个结果为:
[
{
"_id": "a1713bed-4c8b-46e7-bb68-259045dffdb4",
"name": "First Up Consultants | Bed and Bath Collection - Jaskolskiside",
"company": "First Up Consultants",
"citiesForCompany": [
"South Thelma",
"South Carmenview",
"Port Antone",
"Charlotteville",
"South Lenorafort",
"Jaskolskiside"
]
},
{
"_id": "6b8585ab-4357-4da7-8625-f6a1cd5796c5",
"name": "First Up Consultants | Computer Depot - West Zack",
"company": "First Up Consultants",
"citiesForCompany": [
"South Thelma",
"South Carmenview",
"Port Antone",
"Charlotteville",
"South Lenorafort",
"Jaskolskiside",
"West Zack"
]
}
]