Question

给出以下示例，我想查询包含两个文档（{x：30，y：40} {x：40，y：50}，与“时间”无关）的_id。但是x和y需要过滤。

{
        "_id" : ObjectId("5caa04c6eef934095e66ebc5"),
        "position" : [
                {
                        "x" : 30,
                        "y" : 40,
                        "time" : ISODate("2019-03-28T14:00:00Z")
                },
                {
                        "x" : 40,
                        "y" : 50,
                        "time" : ISODate("2019-03-28T14:00:00Z")
                },
                {
                        "x" : 50,
                        "y" : 60,
                        "time" : ISODate("2019-03-28T14:00:00Z")
                }
        ]
}

例如（无效）：

db.testes.find({position: {$all: [{x:{$gt:28,$lte:32}, y:{$gt:38,$lte:42}, time:{$gte: ISODate("2019-03-28T14:00:00Z")}}, {x:{$gt:38,$lte:42}, y:{$gt:48,$lte:52}, time: {$gte: ISODate("2019-03-28T14:00:00Z")}}]}})

或

db.testes.find({position: {$all: [{x:{$gt:28,$lte:32}, y:{$gt:38,$lte:42}}, {x:{$gt:38,$lte:42}, y:{$gt:48,$lte:52}}]}})

但这可行：

db.testes.find({position: {$all: [{x:30, y:40, time:ISODate("2019-03-28T14:00:00Z")}, {x:40, y:50, time:ISODate("2019-03-28T14:00:00Z")}]}})

感谢您的帮助

Answer 1

请尝试这个

$ helm version
Client: &version.Version{SemVer:"v2.13.1", GitCommit:"618447cbf203d147601b4b9bd7f8c37a5d39fbb4", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.13.1", GitCommit:"618447cbf203d147601b4b9bd7f8c37a5d39fbb4", GitTreeState:"clean"}

Answer 2

您可以通过$project（$filter）在MongoDb aggregation内过滤子文档数组。尝试如下操作：

db.collection.aggregate([
    {
        $project: {
            position: {
                $filter: {
                    input: "$position",
                    as: "pos",
                    cond: {
                        $or: [
                            { $and: [ { $eq: [  "$$pos.x", 30 ] },  { $eq: [  "$$pos.y", 40 ] } ] },
                            { $and: [ { $eq: [  "$$pos.x", 40 ] },  { $eq: [  "$$pos.x", 50 ] } ] }
                        ]
                    }
                }
            }
        }
    }
])

您将获得的结果如下：

{
    "_id" : ObjectId("5caa04c6eef934095e66ebc5"),
    "position" : [
        {
            "x" : 30,
            "y" : 40,
            "time" : ISODate("2019-03-28T19:30:00.000+05:30")
        }
    ]
}

如何查询至少两个文档满足过滤条件的嵌入式文档数组

2 个答案: