如何将mongodb对象数据聚合数组分组为同一日期的数字和

Question

我试图创建图表，但我不能将数据组合成“预期结果”

我可以用什么来返回“预期的结果”。

我试着在$group和$reduce中使用$group和$reduce，但效果不太好。

我希望有人能帮我解决这个问题。

当前的结果是

[
   {
      "_id":"5fd4c3586e83b334d97c5218",
      "consumption":5,
      "charts":[
         {
            "date":"2020-10",
            "consumption":1
         },
         {
            "date":"2020-10",
            "consumption":1
         },
         {
            "date":"2020-11",
            "consumption":1
         },
         {
            "date":"2020-11",
            "consumption":1
         }
      ]
   }
]

预期结果为

[
   {
      "_id":"5fd4c3586e83b334d97c5218",
      "consumption":5,
      "charts":[
         {
            "date":"2020-10",
            "consumption":2
         },
         {
            "date":"2020-11",
            "consumption":2
         },
   }
]

Answer 1

您需要使用聚合。

db.collection.aggregate([
  { $unwind: "$charts" },
  {
    $group: {
      _id: { _id: "$_id", month: "$charts.date.month", year: "$charts.date.year" },
      consumption: { $first: "$consumption" },
      total: { $sum: "$charts.consumption" },
      date: { $first: "$charts.date" }
    }
  },
  {
    $group: {
      _id: "$_id._id",
      consumption: { $first: "$consumption" },
      charts: {
        $push: {
          date: "$date",
          consumption: "$total"
        }
      }
    }
  }
])

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