How to add these Key Value in array in mongo db?-CodePudding

Given 1st block of code is the sample data and the second block is my desired output What is the query needed to add the fields of Machine Stats in MongoDB So that my desired output is this (basically addition of all the fields in machine stats array)

{
    "date" : ISODate("2022-04-01T00:00:00.000Z"),
    "intervalName" : "Shift A",
    "operatorId" : "85875678",
    "__v" : 0,
    "clientId" : "ywegduywy",
    "createdAt" : ISODate("2022-05-05T07:33:08.183Z"),
    "deleted" : false,
    "machineStats" : [ 
        {
            "idleTime" : 10,
            "breaks" : 10,
            "loading" : 10,
            "unloading" : 10,
            "runtime" : 11,
            "total" : 100,
            "activity" : {}
        }, 
        {
            "idleTime" : 10,
            "breaks" : 10,
            "loading" : 10,
            "unloading" : 10,
            "runtime" : 10,
            "total" : 100,
            "activity" : {}
        }
    ],
    "plantId" : "AACCS3034M-SEZ-01",
    "totalActivity" : 10,
    "totalAll" : 100,
    "totalBreaks" : 10,
    "totalIdleTime" : 10,
    "totalLoadUnload" : 10,
    "totalRuntime" : 10,
    "updatedAt" : ISODate("2022-05-05T07:33:30.213Z")
}

Desired output I Want (basically addition of all the fields in machine stats array except activities)

{
    "date" : ISODate("2022-04-01T00:00:00.000Z"),
    "intervalName" : "Shift A",
    "operatorId" : "495632582487",
    "__v" : 0,
    "clientId" : "AACCS3034M",
    "createdAt" : ISODate("2022-05-05T07:33:08.183Z"),
    "deleted" : false,
    "machineStats" : [ 
        {
            "idleTime" : 20,
            "breaks" : 20,
            "loading" : 20,
            "unloading" :20,
            "runtime" : 21,
            "total" : 200,
            "activity" : {}
        }, 
       
    ],
    "plantId" : "AACCS3034M-SEZ-01",
    "totalActivity" : 10,
    "totalAll" : 100,
    "totalBreaks" : 10,
    "totalIdleTime" : 10,
    "totalLoadUnload" : 10,
    "totalRuntime" : 10,
    "updatedAt" : ISODate("2022-05-05T07:33:30.213Z")
}

CodePudding user response：

One way to do it is using $reduce to iterate over the array and add each item's data to the cumulative data, like this:

db.collection.aggregate([
  {
    $set: {
      machineStats: {
        $reduce: {
          input: "$machineStats",
          initialValue: {
            idleTime: 0,
            breaks: 0,
            loading: 0,
            unloading: 0,
            runtime: 0,
            total: 0
          },
          in: {
            idleTime: {$add: ["$$value.idleTime", "$$this.idleTime"]},
            breaks: {$add: ["$$value.breaks", "$$this.breaks"]},
            loading: {$add: ["$$value.loading", "$$this.loading"]},
            unloading: {$add: ["$$value.unloading", "$$this.unloading"]},
            total: {$add: ["$$value.total", "$$this.total"]},
            runtime: {$add: ["$$value.runtime", "$$this.runtime"]}
          }
        }
      }
    }
  }
])

Playground example.

Another option is to use $unwind and $group but it should be less efficient for this specific requested output.

CodePudding user response：

You can use map and reduce methods to complete this kind of calculation in a mongo query.