MongoDB : - 将具有相同键的对象合并为一个答案

【问题标题】：MongoDB : - Merge object with same key into oneMongoDB : - 将具有相同键的对象合并为一个
【发布时间】：2023-01-09 01:25:14
【问题描述】：

我正在尝试合并数组中具有相同日期但 status 键具有不同键名的对象。

我有 2 个系列 users 和 canteens

我正在尝试获取结果但无法弄清楚如何将对象与相同的 Date 合并的查询

输出

User.aggregate([
    { $sort: { workerId: 1 } },
    {
      $lookup: {
        from: "canteens",
        localField: "_id",
        foreignField: "employeeId",
        pipeline: [
          {
            $match: {
              Date: {
                $gte: new Date(fromDate),
                $lte: new Date(toDate),
              },
            },
          },
          {
            $project: {
              Date: 1,
              status: 1,
            },
          },
        ],
        as: "canteens",
      },
    },
    {
      $project: {
        _id: 1,
        workerId: 1,
        workerFirstName: 1,
        workerSurname: 1,
        workerDepartment: 1,
        workerDesignation: 1,
        locationName: 1,
        canteenData: "$canteens",
      },
    },
  ]);

[
  {
    "_id": "60e6fd3616dd663e84a925e2",
    "workerFirstName": "Firstaname",
    "workerSurname": "lastname",
    "workerId": "1",
    "locationName": "location",
    "workerDesignation": "designation",
    "workerDepartment": "department",
    "canteenData": [
      {
        "_id": "63b285b9e92eee614feb7be1",
        "status": "LUNCH",
        "Date": "2023-01-02T00:00:00.000Z"
      },
      {
        "_id": "63b2db8db10c24487201e0a2",
        "status": "DINNER",
        "Date": "2023-01-02T00:00:00.000Z"
      },
      {
        "_id": "63b39b247adbeb50bfbe3503",
        "status": "BREAK FAST",
        "Date": "2023-01-03T00:00:00.000Z"
      },
      {
        "_id": "63b3d248c076184fb07ff2c4",
        "status": "LUNCH",
        "Date": "2023-01-03T00:00:00.000Z"
      },
      {
        "_id": "63b42b8ccb57a4cb7af34015",
        "status": "DINNER",
        "Date": "2023-01-03T00:00:00.000Z"
      },
      {
        "_id": "63b4ef71e038498fe6634506",
        "status": "BREAK FAST",
        "Date": "2023-01-04T00:00:00.000Z"
      }
    ]
  },
{
    "_id": "60e6fd3616dd663e84a925e2",
    "workerFirstName": "Firstaname1",
    "workerSurname": "lastname1",
    "workerId": "2",
    "locationName": "location",
    "workerDesignation": "designation",
    "workerDepartment": "department",
    "canteenData": [
      {
        "_id": "63b285b9e92eee614feb7be1",
        "status": "LUNCH",
        "Date": "2023-01-02T00:00:00.000Z"
      },
      {
        "_id": "63b2db8db10c24487201e0a2",
        "status": "DINNER",
        "Date": "2023-01-02T00:00:00.000Z"
      },
      {
        "_id": "63b39b247adbeb50bfbe3503",
        "status": "BREAK FAST",
        "Date": "2023-01-03T00:00:00.000Z"
      },
      {
        "_id": "63b3d248c076184fb07ff2c4",
        "status": "LUNCH",
        "Date": "2023-01-03T00:00:00.000Z"
      },
      {
        "_id": "63b42b8ccb57a4cb7af34015",
        "status": "DINNER",
        "Date": "2023-01-03T00:00:00.000Z"
      },
      {
        "_id": "63b4ef71e038498fe6634506",
        "status": "BREAK FAST",
        "Date": "2023-01-04T00:00:00.000Z"
      }
    ]
  }
]

我试图获得的输出


[
  {
    "_id": "60e6fd3616dd663e84a925e2",
    "workerFirstName": "Firstanem",
    "workerSurname": "lastname",
    "workerId": "1",
    "locationName": "location",
    "workerDesignation": "designation",
    "workerDepartment": "department",
    "canteenData": [
      {
        "_id": "63b285b9e92eee614feb7be1",
        "status1": "LUNCH",
        "status2": "DINNER",
        "Date": "2023-01-02T00:00:00.000Z"
      },
      {
        "_id": "63b39b247adbeb50bfbe3503",
        "status1": "BREAK FAST",
        "status2": "LUNCH",
        "status3": "DINNER",
        "Date": "2023-01-03T00:00:00.000Z"
      },
      {
        "_id": "63b4ef71e038498fe6634506",
        "status1": "BREAK FAST",
        "Date": "2023-01-04T00:00:00.000Z"
      }
    ]
  },
{
    "_id": "60e6fd3616dd663e84a925e2",
    "workerFirstName": "Firstanem1",
    "workerSurname": "lastname1",
    "workerId": "2",
    "locationName": "location",
    "workerDesignation": "designation",
    "workerDepartment": "department",
    "canteenData": [
      {
        "_id": "63b285b9e92eee614feb7be1",
        "status1": "LUNCH",
        "status2": "DINNER",
        "Date": "2023-01-02T00:00:00.000Z"
      },
      {
        "_id": "63b39b247adbeb50bfbe3503",
        "status1": "BREAK FAST",
        "status2": "LUNCH",
        "status3": "DINNER",
        "Date": "2023-01-03T00:00:00.000Z"
      },
      {
        "_id": "63b4ef71e038498fe6634506",
        "status1": "BREAK FAST",
        "Date": "2023-01-04T00:00:00.000Z"
      }
    ]
  }
]

【问题讨论】：

标签： javascript mongodb mongoose merge aggregation-framework

【解决方案1】：

一种选择是在您的$lookup 管道聚合中添加 2 个步骤：

  {$group: {
      _id: "$Date",
      _idVal: {$first: "$_id"},
      data: {$addToSet: "$status"}
  }},
  {$replaceRoot: {
      newRoot: {
        $mergeObjects: [
          {_id: "$_idVal", Date: "$_id"},
          {$arrayToObject: {
              $reduce: {
                input: "$data",
                initialValue: [],
                in: {$concatArrays: [
                    "$$value",
                    [{k: {$concat: [
                            "status",
                            {$toString: {$add: [{$size: "$$value"}, 1]}}
                          ]},
                      v: "$$this"}]
                ]}
              }
          }}
        ]
      }
  }}

查看它在playground example 上的工作原理

【讨论】：