MongoDb聚合查询问题

我有一个MongoDB表DOCUMENTS，其中包含国家/地区、月份和交付合作伙伴名称列，
它们如下所示-

[{
        "id": "1",
        "month": "Jan",
        "deliveryPartner": {
            "name": "Lalamove"
        },
        "country": "ID"
    },
    {
        "id": "2",
        "month": "Jan",
        "deliveryPartner": {
            "name": "Lalamove"
        },
        "country": "ID"
    },
    {
        "id": "3",
        "month": "Jan",
        "deliveryPartner": {
            "name": "Borzo"
        },
        "country": "ID"
    },
    {
        "id": "4",
        "month": "Jan",
        "deliveryPartner": {
            "name": "Lalamove"
        },
        "country": "PH"
    },
    {
        "id": "5",
        "month": "Jan",
        "deliveryPartner": {
            "name": "Borzo"
        },
        "country": "PH"
    },
    {
        "id": "6",
        "month": "Feb",
        "deliveryPartner": {
            "name": "Borzo"
        },
        "country": "ID"
    },
    {
        "id": "7",
        "month": "Feb",
        "deliveryPartner": {
            "name": "Borzo"
        },
        "country": "ID"
    },
    {
        "id": "8",
        "month": "Feb",
        "deliveryPartner": {
            "name": "Lalamove"
        },
        "country": "PH"
    }
]

我想要编写一个聚合查询，它会给出如下所示的输出-

[
    {
        "deliveryPartner": "Lalamove",
        "country": "ID",
        "month": [
            {
                "Jan": 2
            },
            {
                "Feb": 0
            }
        ]
    },
    {
        "deliveryPartner": "Borzo",
        "country": "ID",
        "month": [
            {
                "Jan": 1
            },
            {
                "Feb": 2
            }
        ]
    },
    {
        "deliveryPartner": "Lalamove",
        "country": "PH",
        "month": [
            {
                "Jan": 1
            },
            {
                "Feb": 1
            }
        ]
    },
    {
        "deliveryPartner": "Borzo",
        "country": "PH",
        "month": [
            {
                "Jan": 1
            },
            {
                "Feb": 0
            }
        ]
    }
]

我try 了以下查询，但输出不是预期的结果-

let result = await con.aggregate([
    { $match : { year : "2023", "deliveryPartner.name": { $ne: null }, "country": { $ne: null }, "month": { $ne: null } } },
    {
      $group: {
        _id: {
          deliveryPartner: "$deliveryPartner.name",
          country: "$country",
          month: "$month"
        },
        count: { $sum: 1 }
      }
    },
    {
      $group: {
        _id: {
          deliveryPartner: "$_id.deliveryPartner",
          country: "$_id.country"
        },
        monthData: {
          $push: {
            month: "$_id.month",
            count: "$count"
          }
        }
      }
    }
  ]).toArray();

  console.log("result => ", JSON.stringify(result));

输出不会将缺少的月份计数设置为0