Question

我正在尝试使用$lookup进行聚合。我的“引号”包含每个引用的文档，如下所示

{
    "_id" : "11223344",
    "_etag" : ObjectId("58b7fe8c3df03c1594ab0c45"),
    "vehicles" : [ 
        "1122334455", 
        "1122334456"
    ]
}

现在车辆是另一个集合，如下所示

{
    "_id" : "1122334455",
    "referenceNumber" : "11223344",
    "sequenceNumber" : 15,
    "status" : {
        "statusCode" : "consectetur amet fugiat id",
        "statusDesc" : "exercitation"
    },
    "trackerInstalled" : true,
    "vehicleDetails" : {
        "year" : "2012",
        "make" : "Toyota",
        "model" : "Corrola"
    },
    "riskPremium" : "99.00",
    "_etag" : ObjectId("58b91f6d1cdd923b3ce7f091")
}

{
    "_id" : "1122334456",
    "referenceNumber" : "11223344",
    "sequenceNumber" : 16,
    "status" : {
        "statusCode" : "consectetur amet fugiat id",
        "statusDesc" : "exercitation"
    },
    "trackerInstalled" : true,
    "vehicleDetails" : {
        "year" : "2012",
        "make" : "BMW",
        "model" : "320d"
    },
    "riskPremium" : "199.00"
}

我想要的是当用户查询为GET / quotes / 1122334455时，我应该向他发送一份报价文件，其中所有车辆都来自车辆集合，如下所示，

{
    "_id" : "11223344",
    "_etag" : ObjectId("58b7fe8c3df03c1594ab0c45"),
    "vehicles" : "1122334455",
    "vehicle_doc" : [ 
        {
            "_id" : "1122334455",
            "referenceNumber" : "11223344",
            "sequenceNumber" : 15,
            "status" : {
                "statusCode" : "consectetur amet fugiat id",
                "statusDesc" : "exercitation"
            },
            "trackerInstalled" : true,
            "vehicleDetails" : {
                "year" : "2012",
                "make" : "Toyota",
                "model" : "Corrola"
            },
            "riskPremium" : "99.00",
            "_etag" : ObjectId("58b91f6d1cdd923b3ce7f091")
        },
{
            "_id" : "1122334456",
            "referenceNumber" : "11223344",
            "sequenceNumber" : 16,
            "status" : {
                "statusCode" : "consectetur amet fugiat id",
                "statusDesc" : "exercitation"
            },
            "trackerInstalled" : true,
            "vehicleDetails" : {
                "year" : "2012",
                "make" : "BMW",
                "model" : "320d"
            },
            "riskPremium" : "199.00"
        }
    ]
}

我使用了以下聚合

db.quotes.aggregate([    
    { $unwind: "$vehicles" },        
    { $lookup: {
        from: "vehicles",
        localField: "vehicles",
        foreignField: "_id",
        as: "vehicle_doc"
    } }
])

但是它给了我两个相同报价的文件，每个文件都包含一个车辆。我如何合并两个文件，只在一个引号中有车辆阵列。

我检查了提到的问题，与我的问题的区别在于我需要保留左侧集合中的其余文档信息，解决方案中的想法假设除了_id之外没有其他项目可以投影，但我还需要传回其余的引用信息。

在Mongodb中的聚合中合并多个文档

0 个答案: