如何对对象数据的mongodb聚合数组进行分组以对同一日期的数字求和

Question

我正在尝试创建图表，但我无法将数据组合成“预期结果如下”

我可以用什么来返回“预期结果”。

我尝试在 $group 和 $reduce 中使用 $group，但效果不佳。

希望有人能帮我解决这个问题

当前结果是

[
   {
      "_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
         }
      ]
   }
]

预期结果是

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

Answer 1

你需要使用聚合

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"
        }
      }
    }
  }
])

工作Mongo playground