组/聚合领域一起

Question

我有我导入到MongoDB的csv文件，它具有以下结构：

我想组这与开始的ID，和其他所有领域作为该儿童的，就像这样：

"_id" : "A" { 
      "destination" : B { 
       "duration" : 5 
       "duration" : 3 
       "duration" : 6 
      } 
      "destination" : C { 
       "duration" : 10 
      } 
    } 
    "_id" : "B" { 
      "destination" : A { 
       "duration" : 4 
      } 
    } 

我理解的MongoDB的聚集命令的基础知识，我想这是基于约杰什的回答是：

db.test.aggregate([ 
{ "$group": { 
    "_id": "$start", 
    "Trips": { 
     "$push": { 
      "Destination" : "$destination", 
      "Duration"  : "$duration" 
     } 
    } 
    } 
}],{allowDiskUse:true}).pretty() 

我的问题是我如何也可以将持续时间分组到那里。眼下，从A 2“旅行”到B，有2项像这样：

{ "Destination": B, 
     "Duration": 5 
    }, 
    { 
     "EndStationID": B, 
     "Duration": 3 
    } 

我怎么能还结合这些成结构是这样的：

{ "Destination": B { 
      "Duration": 5, 
      "Duration": 3 
    } 

Answer 1

根据您的CSV结构我创建下列集合

{ "start" : "A", "destination" : "B", "duration" : 5 } 
{ "start" : "A", "destination" : "B", "duration" : 3 } 
{ "start" : "A", "destination" : "B", "duration" : 6 } 
{ "start" : "B", "destination" : "A", "duration" : 4 } 

首先，你应该group起点和目标字段，然后按持续时间分成数组，从而下面聚集查询：

db.collectionName.aggregate({ 
    "$group": { 
    "_id": { 
     "start": "$start", 
     "dest": "$destination" 
    }, 
    "duration": { 
     "$push": { 
      "duration": "$duration" 
     } 
    } 
    } 
}, { 
    "$project": { 
    "_id": "$_id.start", 
    "destination": "$_id.dest", 
    "duration": 1 
    } 
}).pretty()