如何在 MongoDB 中做一个 pivot 和条件组？

Question

我有这样的数据：

[
  {
    "invoice_id": "GRS",
    "segment": "D",
    "metric": "2019",
    "revenue": 100,
  },
  {
    "invoice_id": "RET",
    "segment": "D",
    "metric": "2019",
    "revenue": 100,
  },
  {
    "invoice_id": "GRS",
    "segment": "R",
    "metric": "2020",
    "revenue": 100,
  },
  {
    "invoice_id": "RET",
    "segment": "R",
    "metric": "2021",
    "revenue": 100,
  },
  {
    "invoice_id": "GRS",
    "segment": "R",
    "metric": "2021",
    "revenue": 100,
  },
  {
    "invoice_id": "RET",
    "segment": "D",
    "metric": "2020",
    "revenue": 100,
  },
  {
    "invoice_id": "GRS",
    "segment": "D",
    "metric": "2021",
    "revenue": 100,
  }
]

聚合后，我希望结果采用以下格式：

[
  {
    "invoice_id": "GRS",
    "segment": "D",
    "2019": 100,
    "2021": 100
  },
  {
    "invoice_id": "RET",
    "segment": "D",
    "2019": 100,
    "2020": 100
  },
  {
    "invoice_id": "GRS",
    "segment": "R",
    "2019": 100,
    "2021": 100
  },
  {
    "invoice_id": "RET",
    "segment": "R",
    "2021": 100
  },
]

Answer 1

• $group by invoice_id , segment和metric并获得总revenue
• $group by invoice_id和segment并在键值对中构造年份数组
• $arrayToObject将years数组转换为 object 键值格式
• $mergeObject合并_id object 和years object
• $replaceRoot替换上述合并 object 到 root

db.collection.aggregate([
  {
    $group: {
      _id: {
        invoice_id: "$invoice_id",
        segment: "$segment",
        metric: "$metric"
      },
      revenue: { $sum: "$revenue" }
    }
  },
  {
    $group: {
      _id: {
        invoice_id: "$_id.invoice_id",
        segment: "$_id.segment"
      },
      years: {
        $push: {
          k: "$_id.metric",
          v: "$revenue"
        }
      }
    }
  },
  {
    $replaceRoot: {
      newRoot: {
        $mergeObjects: [
          "$_id",
          { $arrayToObject: "$years" }
        ]
      }
    }
  }
])

操场