Mongodbでの集約に関する集計

Question

私は、インドに州、郡、村を持つ文書のmongoコレクションを持っています。以下の形式で、私はそのI結果、このような方法で、状態、地区や村でグループにそれをしたい

{ 
    "_id" : ObjectId("58db5a5f8f7b5013ad477564"), 
    "district" : "Chittor", 
    "state" : "Andhra Pradesh", 
    "village" : "Chittoor" 
}, 
{ 
    "_id" : ObjectId("58db5a628f7b5013ad477566"), 
    "district" : "Dibrugarh", 
    "state" : "Assam", 
    "village" : "Dibrugarh" 
}, 
{ 
    "_id" : ObjectId("58db5a628f7b5013ad47756d"), 
    "district" : "Lakhimpur", 
    "state" : "Assam", 
    "village" : "Kadam" 
}, 
{ 
    "_id" : ObjectId("58db5a628f7b5013ad47756e"), 
    "district" : "Sonitpur", 
    "state" : "Assam", 
    "village" : "Helem" 
}, 
{ 
    "_id" : ObjectId("58db5a628f7b5013ad477572"), 
    "district" : "Gandhinagar", 
    "state" : "Gujarat", 
    "village" : "Mansa" 
}, 
{ 
    "_id" : ObjectId("58db5a628f7b5013ad477573"), 
    "district" : "Gandhinagar", 
    "state" : "Gujarat", 
    "village" : "Kalol" 
}, 
{ 
    "_id" : ObjectId("58db5a628f7b5013ad477574"), 
    "district" : "Ahmadabad", 
    "state" : "Gujarat", 
    "village" : "Barwala" 
} 

[ 
    { 
    "state": "Gujarat", 
    "districts": [ 
     { 
     "district": "Gandhinagar", 
     "villages": [ 
      { 
      "village": "Mansa" 
      }, 
      { 
      "village": "Kalol" 
      } 
     ] 
     }, 
     { 
     "district": "Ahmadabad", 
     "villages": [ 
      { 
      "village": "Barwala" 
      } 
     ] 
     } 
    ] 
    }, 
    { 
    "state": "Assam", 
    "districts": [ 
     { 
     "district": "Sonitpur", 
     "villages": [ 
      { 
      "village": "Helem" 
      } 
     ] 
     }, 
     { 
     "district": "Lakhimpur", 
     "villages": [ 
      { 
      "village": "Kadam" 
      } 
     ] 
     }, 
     { 
     "district": "Dibrugarh", 
     "villages": [ 
      { 
      "village": "Dibrugarh" 
      } 
     ] 
     } 
    ] 
    }, 
    { 
    "state": "Andhra Pradesh", 
    "districts": [ 
     { 
     "district": "Chittor", 
     "villages": [ 
      { 
      "village": "Chittor" 
      } 
     ] 
     } 
    ] 
    } 
] 

私が試みたが、このような凝集を取得する方法を見つけることができませんでした。

1) db.historical_prices.aggregate({$group: {_id: {"state": "$state"}}}, {$group: {_id: {"commodity": "$commodity"}}}) 

2) db.places.aggregate() 
     .match(qb.where("enabled").eq(false)) 
     .group({ _id: {"state": "$state", "district": "$district"}, "districts": {$push: {district: "$district"}}, }) 

elasticsearchでは、このような種類の集約が行われました。

どうすればMongoDBで取得できますか？私はelasticsearchを使用したくないからです。

Answer 1

以下の集計を試すことができます。以下のクエリ$groupをstateおよびdistrictに集めてvillagesを蓄積し、続いて$groupをstateに集めてdistrictを蓄積し、先にvillagesを収集する。

db.collection.aggregate([{ 
    $group: { 
     _id: {state:"$state", district:"$district"}, 
     "villages":{$addToSet:{village:"$village"}} 
    } 
},{ 
    $group: { 
     _id: {state:"$_id.state"}, 
     "districts":{$push:{villages:"$villages", district:"$_id.district"}} 
    } 
}])