Node.js mongoDB加入MERN Stack项目

我有两个收藏，我想加入他们。（请用Mongo 3.6语法指导我）。产品：

 {
        "_id": "5b55c3b303d3a94e0c11e634",
        "createdAt": "2018-07-23T12:01:55.760Z",
        "updatedAt": "2018-07-23T12:01:55.760Z",
        "address": "1111 West Chicago Avenue, Chicago, IL 60642",
        "lang": "en",
        "poster": "/images/products/poster/pizzzzza.jpg",
        "new_price": 45,
        "off": 10,
        "old_price": 50,
        "summary": "10% Cash Back at Pie-Eyed Pizzeria",
        "title": "Pie-Eyed Pizzeria",
        "status": true,
        "category_id": "5b449e6b6f94bb4ab0b67b70"
    },
    {
        "_id": "5b55c34a03d3a94e0c11e631",
        "createdAt": "2018-07-23T12:00:10.409Z",
        "updatedAt": "2018-07-23T12:00:10.409Z",
        "address": "505 N. Lake Shore Dr. Suite #204, Chicago, IL 60611",
        "lang": "en",
        "poster": "/images/products/poster/asdasd.jpg",
        "new_price": 34,
        "off": 66,
        "old_price": 100,
        "summary": "No-Chip Mani-Pedi at MC Lash Studio (Up to 66% Off). Three Options Available.",
        "title": "MC Lash Studio",
        "status": true,
        "category_id": "5b449cf96f94bb4ab0b67b6b"
    }

我的第二个收藏是ProductDetails：

{
"_id" : ObjectId("5b55c3b703d3a94e0c11e635"),
"createdAt" : ISODate("2018-07-23T16:31:59.323+04:30"),
"updatedAt" : ISODate("2018-07-23T16:31:59.323+04:30"),
"location" : "",
"detail" : "Enter your Detail",
"terms_of_use" : "Enter terms of use",
"description" : "Enter your description",
"product_id" : "5b55c3b303d3a94e0c11e634"

},

}

我想在mongodb里有这样的东西

select * from Products left join ProductDetails on Products._id = ProductDetails.product_id

我尝试了$lookup，但不知道如何在$match中输入“Products.\u id”

从“../models/ProductsModel.js”导入产品；
导出函数getProductDetail（req、res、next）{
产品.聚合(
{
$lookup：
{
来自：“产品详细信息”，
管道：[{$match:{product\u id:Products.\u id}}]，
as:“产品详细信息”
}
})
}

您需要定义管道阶段，然后将它们传递给聚合函数，如下所示：

import Products from '../models/ProductsModel.js';
export function getProductDetail(req, res, next){
        // Pipeline stages definition 
        const pipeline = [
            { $match: {
                    "_id" : "5b55c3b303d3a94e0c11e634" // From you request params
                }
            },
            {$lookup: {
                    from: "ProductDetails",
                    localField: "_id",
                    foreignField: "product_id",
                    as: "details"
                }
            }
        ];
        Products.aggregate(pipeline).exec()
            .then((products) => {
                // Handle your response
            })
            .catch(err => {
                next(err);
            });
}

---

不工作，错误消息是：参数必须是聚合管道运算符我忘记了$match和$lockup运算符，请检查此新查询

import Products from '../models/ProductsModel.js';
export function getProductDetail(req, res, next){
        // Pipeline stages definition 
        const pipeline = [
            { $match: {
                    "_id" : "5b55c3b303d3a94e0c11e634" // From you request params
                }
            },
            {$lookup: {
                    from: "ProductDetails",
                    localField: "_id",
                    foreignField: "product_id",
                    as: "details"
                }
            }
        ];
        Products.aggregate(pipeline).exec()
            .then((products) => {
                // Handle your response
            })
            .catch(err => {
                next(err);
            });
}