MongoDB按月和年统计属性和分组的值

Question

我的 mongodb 中有文档，我尝试计算我拥有的每一个相同的描述并分类到他们创建的月份。

我想返回一个数组，其中包含对象数组，其中包含月份数和描述值的子数组和计数。

我希望能够选择要计算的描述值并选择他将在哪一年向我显示数据 例如这是我的文件：

    [
  {
    "username": "ron",
    "skills": [
      {
        "rank": "high",
        list: [
          {
            "subject": "Football"
          },
          {
            "subject": "Swim"
          }
        ]
      },
      {
        "rank": "low",
        list: [
          {
            "subject": "Baseball"
          },
          
        ]
      }
    ],
    "duration": 0,
    "date": ISODate("2021-07-24T12:05:27.127Z"),
    "createdAt": ISODate("2021-07-24T12:05:49.985Z"),
    "updatedAt": ISODate("2021-07-24T12:05:49.985Z"),
    "__v": 0
  },
  {
    "username": "john",
    "skills": [
      {
        "rank": "low",
        list: [
          {
            "subject": "Football"
          },
          
        ]
      }
    ],
    "duration": 0,
    "date": ISODate("2021-07-25T12:05:53.000Z"),
    "createdAt": ISODate("2021-07-24T12:05:59.249Z"),
    "updatedAt": ISODate("2021-07-24T12:05:59.249Z"),
    "__v": 0
  },
  {
    "username": "david",
    "skills": [
      {
        "rank": "high",
        list: [
          {
            "subject": "Football"
          },
          {
            "subject": "Baseball"
          }
        ]
      },
      {
        "rank": "low",
        list: [
          {
            "subject": "Swim"
          },
          
        ]
      }
    ],
    "duration": 0,
    "date": ISODate("2021-08-26T12:06:13.000Z"),
    "createdAt": ISODate("2021-07-24T12:06:21.328Z"),
    "updatedAt": ISODate("2021-07-24T12:06:21.328Z"),
    "__v": 0
  },
  {
    "username": "david",
    "skills": [
      {
        "request": "high",
        list: [
          {
            "subject": "Swim"
          },
          
        ]
      },
      {
        "request": "low",
        list: [
          {
            "subject": "Football"
          },
          {
            "subject": "Baseball"
          },
          
        ]
      }
    ],
    "duration": 0,
    "date": ISODate("2021-01-21T13:07:50.000Z"),
    "createdAt": ISODate("2021-07-24T12:08:05.552Z"),
    "updatedAt": ISODate("2021-07-24T12:14:51.285Z"),
    "__v": 0
  },
  {
    "username": "david",
    "skills": [
      {
        "rank": "high",
        list: [
          {
            "subject": "Football"
          },
          
        ]
      },
      
    ],
    "duration": 0,
    "date": ISODate("2022-01-21T13:07:50.000Z"),
    "createdAt": ISODate("2022-07-24T12:08:05.552Z"),
    "updatedAt": ISODate("2022-07-24T12:14:51.285Z"),
    "__v": 0
  }
]

如果我只想匹配等于“足球”或“棒球”的描述，我希望得到的结果：

 {
    [ {"month_number":7,"result":[{"description":'Football',"count":2},{"description":"Baseball","count":1}]},
          {"month_number":8,"result":[{"description":'Football',"count":1}]}]
}

我是 mongodb 的新手......到目前为止，我已经能够计算每个值的数量并只显示我想要的值，但我不知道如何根据我的年份将其分类为几个月选择。

我试过了：

db.exercises.aggregate([{$match:{ $and:[{description:{$in: ["Baseball","Football"]}}]}} ,{$group:{_id:"$description",count:{$sum:1}}}])

还有这个

db.exercises.aggregate(
  [
    {
      $project:
        {
          _id: 0,
          year: { $year: "$date" },
          month: { $month: "$date" },
          description:"$description"
        }
    },
    {
        $match:{$and:[{description:{$in: ["Baseball","Football","Swim"]},year:2021}]}
     },
     {$group:{_id:"$description" , count:{$sum:1}}}
     
  ]
)

Answer 1

您需要再添加 1 个分组，即按月。

工作playground

db.collection.aggregate([
  {
    $project: {
      _id: 0,
      year: {
        $year: "$date"
      },
      month: {
        $month: "$date"
      },
      description: "$description"
    }
  },
  {
    $match: {
      $and: [
        {
          description: {
            $in: [
              "Baseball",
              "Football",
              "Swim"
            ]
          },
          year: 2021
        }
      ]
    }
  },
  {
    $group: {
      _id: {
        description: "$description",
        month: "$month"
      },
      count: {
        $sum: 1
      }
    }
  },
  {
    $group: {
      _id: {
        month_number: "$_id.month"
      },
      results: {
        $push: {
          description: "$_id.description",
          count: "$count"
        }
      }
    }
  },
  {
    $project: {
      _id: 0,
      month_number: "$_id.month_number",
      results: 1
    }
  }
])