Aggregate data in same collection using name

July 25, 2022

I am new to mongo please help me to merge the different data sets with the same block and floor name into one dataset, Actually, the below format is in one database collection with 4 data-set.
can anyone help me to solve this problem in nodejs and mongo?
I tried many ways to solve this issue but I didn’t get any proper output, please help me as soon as possible, thanks in advance

[{
BlockName:"B1",
FloorName:"F1"
Units:[{
       UnitName:104,
       Location:["Hall","Living"]
     }]
},

{
BlockName:"B1",
FloorName:"F2"
Units:[{
        UnitName:104,
        Location:["Hall","Living"]
     }]
},

{
BlockName:"B2",
FloorName:"F1"
Units:[{
       UnitName:104,
       Location:["Hall","Living"]
     }]
},

{
BlockName:"B2",
FloorName:"F2"
Units:[{
       UnitName:104,
       Location:["Hall","Living"]
     }]
}]

I need an output structure like this below:-

[{
BlockName:"B1",
Floors:[
    {
        FloorName:"F1"
        Units:[{
            UnitName:104,
            Location:["Hall","Living"]
        }]
    },
    {
        FloorName:"F2"
        Units:[{
            UnitName:104,
            Location:["Hall","Living"]
        }]
    }
]
},
{
BlockName:"B2",
Floors:[
    {
        FloorName:"F1"
        Units:[{
            UnitName:104,
            Location:["Hall","Living"]
        }]
    },
    {
        FloorName:"F2"
        Units:[{
            UnitName:104,
            Location:["Hall","Living"]
        }]
    }
]
}]

I am new to mongo please help me to merge the different data set with the same block and floor name into one dataset, Actually, the below format is in one database collection with 4 data-set
can anyone help me to solve this problem in nodejs and mongo
I tried many way to solve this issue but I didn't get any proper output, please help me as soon as possible, thanks in advance

>Solution :

$group – Group by BlockName and push the documents into Floors array.
$project – Decorate output documents.

db.collection.aggregate([
  {
    $group: {
      _id: "$BlockName",
      Floors: {
        $push: {
          "FloorName": "$FloorName",
          "Units": "$Units"
        }
      }
    }
  },
  {
    $project: {
      _id: 0,
      BlockName: "$_id",
      Floors: 1
    }
  }
])

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