Question

我有一个集合，并且那个集合有数组，我想找到那个文档的数组ID？

"_id" : ObjectId("5cde81d5f5622a42161c6065"), 
"PhoneNumber" : "PhoneNumber", 
"Nick" : "Nick", 
"Token" : "Token1", 
"MiniProfilePhoto" : "MiniPhoto", 
"IsAndroid" : 1.0, 
"ProfilePhotoId" : 0.0, 
"ProfilePhotoKey" : 0.0, 
"FriendMessages" : [

], 
"Friends" : [
    {
        "FriendId" : ObjectId("5cde84a5f5622a42161c6068"), 
        "FriendState" : 2.0
    }, 
    {
        "FriendId" : ObjectId("5cde740df5622a42161c6061"), 
        "FriendState" : 0.0
    }
]


"_id" : ObjectId("5cde740df5622a42161c6061"), 
"PhoneNumber" : "PhoneNumber1", 
"Nick" : "Nick2", 
"Token" : "Token4", 
"MiniProfilePhoto" : "MiniPhoto5", 
"IsAndroid" : 1.0, 
"ProfilePhotoId" : 0.0, 
"ProfilePhotoKey" : 0.0, 
"FriendMessages" : [

], 
"Friends" : [
    {
        "FriendId" : ObjectId("5cde81d5f5622a42161c6065"), 
        "FriendState" : 1.0
    }
]


"_id" : ObjectId("5cde84a5f5622a42161c6068"), 
"PhoneNumber" : "PhoneNumber", 
"Nick" : "Nick", 
"Token" : "Token", 
"MiniProfilePhoto" : "MiniPhoto", 
"IsAndroid" : 0.0, 
"ProfilePhotoId" : 0.0, 
"ProfilePhotoKey" : 0.0, 
"FriendMessages" : [

], 
"Friends" : [
    {
        "FriendId" : ObjectId("5cde81d5f5622a42161c6065"), 
        "FriendState" : 2.0
    }
]

...

//这是我的收藏示例，ObjectId("5cde81d5f5622a42161c6065")是两个朋友，ids "FriendId" : ObjectId("5cde84a5f5622a42161c6068")和ObjectId("5cde740df5622a42161c6061")，我想找到ObjectId("5cde84a5f5622a42161c6068")和ObjectId("5cde740df5622a42161c6061")的令牌，我如何找到我的朋友令牌？那是什么聚集物？

Answer 1

这是您的汇总查询，

let query = [
    {
        $match: {
            _id: ObjectId("5cde81d5f5622a42161c6065")
        }
    },
    {
        $project: {
            Friends: 1,
            Token: 1
        }
    },
    {
        $unwind: "$Friends"
    },
    {
        $lookup: {
            from: "tets",
            localField: "Friends.FriendId",
            foreignField: "_id",
            as: "fdata"
        }
    },
    {
        $unwind: { path: "$fdata", preserveNullAndEmptyArrays: true }
    },
    {
        $group: {
            _id: "$_id",
            fdata: { $push: { Token: "$fdata.Token", _id: "$fdata._id" } }
        }
    }
]

db.collection.aggregate(query)

输出：

{
    "_id" : ObjectId("5cde81d5f5622a42161c6065"),
    "fdata" : [
        {
            "Token" : "Token",
            "_id" : ObjectId("5cde84a5f5622a42161c6068")
        },
        {
            "Token" : "Token4",
            "_id" : ObjectId("5cde740df5622a42161c6061")
        }
    ]
}

我如何在mongodb中将文件查找到文件错误中

1 个答案: