Javascript mongodb聚合$sum返回0而不是数组中整数的实际总和

我的文档如下所示:

{
  "_id": "2023-04-08",
  "dailyNotes": [
    {
      "therapyDiscipline": "PT",
      "individual": [
        60,
        45,
        30,
        75,
        55
      ],
      "concurrent": [
        69
      ],
      "coTreat": [
        67
      ]
    }
  ]
}

我想要sum all numbers inside 100 array and create a new doc with only 100 key having the sum of array.

以下是我到目前为止try 过的方法，但没有奏效

{
$group: 
{
  _id: '$_id',
  individual:{
    $sum: '$dailyNotes.individual'
  }
}
}

这将返回:

{
  "_id": "2023-04-08",
  "individual": 0
}

一百零二

我try 过的其他解决方案很少，但它们也得出了0和:

{
$project: {
  individual: {
    $reduce: {
        input: "$dailyNotes.individual", 
        initialValue: 0,
        in: { $sum: [ "$$value", "$$this" ]}
    }
  }
}
}

{
$project: 
{
  individual: {
    $sum: '$dailyNotes.individual'
  }
}
}

谁能解释一下为什么它返回0而不是265，以及如何解决这个问题？

[Update]: (example with multiple(max 3) records)个 对于像这样的文档:

{
   "_id":"2023-04-08",
   "dailyNotes":[
      {
         "therapyDiscipline":"PT",
         "individual":[
            60,
            45,
            30,
            75,
            55
         ]
      },
      {
         "therapyDiscipline":"YT",
         "individual":[
            2,
            4
         ]
      }
   ]
}

它应该返回为:

{
   "_id":"2023-04-08",
   "dailyNotes":[
      {
         "individual":265
      },
      {
         "individual":6
      }
   ]
}