mongodb - 合并不同集合的两个对象并在Mongodb中获取特定数据
问题描述
我有两个系列,产品和订单。
products
收藏看起来像这样。
[
{
"_id": "5efb56741c32133bf43ea9aa",
"title": "Xyz",
"image": "172e4eb73415b3cc8540e651.jpg",
"quantity": "1 Ltr",
"price": 1500,
"status": true,
"creationDate": "2020-06-30T15:12:52.570Z",
"__v": 0
},
{
"_id": "5f0079bd27a734424cb3069a",
"title": "abc",
"image": "122e4eb73413b3cc854n42n1.jpg",
"quantity": "500 ml",
"price": 700,
"status": true,
"creationDate": "2020-06-30T15:12:52.570Z",
"__v": 0
}
]
orders
收藏看起来像这样。
[
{
"_id": "5efca937def27b74fc9f6aa6",
"products": [
{
"Date": "2020-07-01T15:14:36.630Z",
"_id": "5efca937def27b74fc9f6aa8",
"productId": "5efb56741c32133bf43ea9aa",
"productQuantity": 2
},
{
"Date": "2020-07-01T15:14:36.630Z",
"_id": "5efca937def27b74fc9f6aa7",
"productId": "5f0079bd27a734424cb3069a",
"productQuantity": 1
}
],
"totalQuantity": 3,
"totalPrice": 3700,
"creationDate": "2020-07-01T15:18:15.756Z",
"__v": 0
},
{
"_id": "5efca897def27b74fc9f6aa2",
"products": [
{
"Date": "2020-07-01T15:14:36.630Z",
"_id": "5efca897def27b74fc9f6aa3",
"productId": "5f0079bd27a734424cb3069a",
"productQuantity": 1
}
],
"totalQuantity": 1,
"totalPrice": 700,
"creationDate": "2020-07-01T15:15:35.422Z",
"__v": 0
}
]
使用这两个集合我怎样才能得到这样的结果:
[
{
"_id": "5efca937def27b74fc9f6aa6",
"products": [
{
"Date": "2020-07-01T15:14:36.630Z",
"_id": "5efca937def27b74fc9f6aa8",
"productId": "5efb56741c32133bf43ea9aa",
"productQuantity": 2,
"title": "Xyz",
"image": "172e4eb73415b3cc8540e651.jpg",
"quantity": "1 Ltr",
"price": 1500
},
{
"Date": "2020-07-01T15:14:36.630Z",
"_id": "5efca937def27b74fc9f6aa7",
"productId": "5f0079bd27a734424cb3069a",
"productQuantity": 1,
"title": "abc",
"image": "122e4eb73413b3cc854n42n1.jpg",
"quantity": "500 ml",
"price": 700
}
],
"totalQuantity": 3,
"totalPrice": 3700,
"creationDate": "2020-07-01T15:18:15.756Z",
"__v": 0
},
{
"_id": "5efca897def27b74fc9f6aa2",
"products": [
{
"Date": "2020-07-01T15:14:36.630Z",
"_id": "5efca897def27b74fc9f6aa3",
"productId": "5f0079bd27a734424cb3069a",
"productQuantity": 1,
"title": "abc",
"image": "122e4eb73413b3cc854n42n1.jpg",
"quantity": "500 ml",
"price": 700
}
],
"totalQuantity": 1,
"totalPrice": 700,
"creationDate": "2020-07-01T15:15:35.422Z",
"__v": 0
}
]
解决方案
我使用这个查询得到了结果。
order.aggregate([
{ "$unwind": "$products" },
{
$lookup: {
from: 'products',
localField: "products.productId",
foreignField: "_id",
as: "product"
}
},
{
"$addFields": {
"products": { $mergeObjects: [{ $arrayElemAt: ["$product", 0] }, "$$ROOT.products"] }
}
},
{
"$group": {
"_id": "$_id",
"products": { "$push": "$products" },
"totalQuantity": { $first: '$totalQuantity' },
"totalPrice": { $first: '$totalPrice' },
"creationDate": { $first: '$creationDate' }
}
}
])
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