mongodb将重复文档分组到一个数组

Question

我试图将特定键的所有文档组织到一个数组中。如果任何其他参数不同，我不想一次又一次地获得相同的关键元素。
样本文件:-

{
    name:"sweta",
    age:23
    address:india,
    hobby:singing
},
{
    name:"john",
    age:24
    address:germany,
    hobby:singing
},
{
    name:"peter",
    age:24
    address:india,
    hobby:dancing
},
{
    name:"marry",
    age:23
    address:india,
    hobby:singing
},

我试过什么？

return db.aggregate([
 {
       $match:{age:23}
 },
 {
       "$group":{
           "_id": {"age":"$age"},
        }
 },
 {   
       "$group":{
           "_id":"$_id.age",
           "name":{ $first: "$_id.name"},
           "address":{ $first: "$_id.address"},
           "hobby":{ $first: "$_id.hobby"},
  }
])

基本上以这种格式分组减少了最大的业务逻辑。

预期答案 =

  [
      {
        "23":[
                {name:"sweta",address:india,hobby:singing},
                {name:"marry",address:india,hobby:singing},
             ]
       },
       {
          "24":[
                {name:"john",address:germany,hobby:singing},
                {name:"peter",address:france,hobby:singing}
             ]
         }

 ]

任何人都知道如何得到这个？

Answer 1

你可以试试这个

db.getCollection('Test').aggregate([
{ $group: { _id: "$age" , 
    data: { $push: {"name":"$name", "address":"$address", "hobby":"$hobby"}},    
    }
},
{ "$replaceRoot": {
    "newRoot": { 
      "$arrayToObject": {
        "$concatArrays": [
          [
            { "k": {$toString: "$_id"}, "v": "$data"  }
          ]
        ]
      } 
    }
  }}
])

结果:

[ {
    "24" : [ 
        { "name" : "john", "address" : "germany", "hobby" : "singing" }, 
        { "name" : "peter", "address" : "india", "hobby" : "dancing" }
    ]
},
{
    "23" : [ 
        { "name" : "sweta", "address" : "india", "hobby" : "singing" }, 
        { "name" : "marry", "address" : "india", "hobby" : "singing" }
    ]
}]