Question

我有一个mongo doc如下：

{
_id: "fe50fdee-4ea3-4824-94af-f369633c0c7a",
_class: "com.tracking.daoservice.model.TrackingData",
modified: ISODate("2014-09-10T23:38:48.407Z"),
eventtype: "William-Test",
eventdata: {
    QueryDate: "01-APR-2014",
    SearchQuery: {
        keyword: "Java",
        location: "Santa Clara, CA",
        Facet: "skill~java~perl|workAuth~USC",
        SearchAgentId: "4299"
    },
    Viewed: [
        {
            ViewedID: "8992ade400a",
            Dockey: "3323aba3233",
            PID: "32399a",
            actionsTaken: "email|direct message|report seeker",
            viewDate: "01-APR-2014",
            MessageSent: "true",
            Message: [
                {
                    MessageID: "123aca323",
                    Delivered: "True",
                    Opened: "True",
                    ClickThroughRate: "NotBad",
                    MessageDate: "02-APR-2014",
                    Response: [
                        {
                            ResponseId: "a323a9da",
                            ResponseDate: "23-APR-2014"
                        }
                    ]
                }
            ]
        }
    ]
},
eventsource: "API-Dev Test - JMachine",
sourceip: "myIp",
entityid: "TmoneyBunnyWunny",
groupid: "Dice",
datecreated: ISODate("2014-09-10T23:38:48.405Z")
}

我有一个关于mongodb的查询，以返回一组id的文档列表

db.TRACKING_DATA.find( {'eventdata.Viewed.Dockey': { $in: ['f7a16badfe6d2729449426ede1d7c558','3ede6f9f94df51bbf97fd9adf566f9d6','34508d254bb3393f52432963426eddc6','591297e6dc75af5aa43581ac66463562','c9fdf22ee4aef3e2f06a624cbafe01ec','b01cbe04b1c7b760b1ac50a953b182dd','e38d86d02a29730be5c7f18c16406fdd','2145ff57990a4d566dae99de05746536','febb0b44f6f481934e8c53a2c603b8a8','30d2ce2934ccbddcd78a16ea1b102765']}, 'entityid': '1026891'})

然而它会返回每个Dockey的所有实例，但是我只想为最近的每个Dockey返回一个，这可以从datecreated属性中看到，有没有办法过滤关于查询的数据只返回这个，即内部查询，它只会为每个Dockey采用最新的文档。

Answer 1

用户聚合管道：

db.TRACKING_DATA.aggregate([
    {
        $match : {
            'eventdata.Viewed.Dockey' : {
                $in : [ 'f7a16badfe6d2729449426ede1d7c558',
                        '3ede6f9f94df51bbf97fd9adf566f9d6',
                        '34508d254bb3393f52432963426eddc6',
                        '591297e6dc75af5aa43581ac66463562',
                        'c9fdf22ee4aef3e2f06a624cbafe01ec',
                        'b01cbe04b1c7b760b1ac50a953b182dd',
                        'e38d86d02a29730be5c7f18c16406fdd',
                        '2145ff57990a4d566dae99de05746536',
                        'febb0b44f6f481934e8c53a2c603b8a8',
                        '30d2ce2934ccbddcd78a16ea1b102765' ]
            },
            'entityid' : '1026891'
        }
    }, {
        $sort : {
            datecreated : -1
        }
    }, {
        $group : {
            _id : "$_id",
            doc : {
                $first : "$$ROOT" // this is whole document for each
                                  // docKey with latest "datecreated"
            }
        }
    } ]);

Mongodb过滤结果集

1 个答案: