聚合：我如何计算该值为真值的键数？

发布于 2025-01-31 08:39:33 字数 667 浏览 2 评论 0原文

我在MongoDB中有很多文档，看起来像这样：

[
  {
    name: "steve",
    accountFeatures: {word: true, excel: false, powerpoint: true}
  },
  {
    name: "john",
    accountFeatures: {word: false, excel: true, powerpoint: true, notes: true}
  },
  {
    name: "rick",
    accountFeatures: {word: true, excel: false, powerpoint: true}
  }
]

我想运行一个聚合以找出对象中的每个键都设置为true（实际数据中还有更多键），所以样本数据的预期输出将是：

  {
    "res": {
      "excel": 1,
      "notes": 1,
      "powerpoint": 3,
      "word": 2
    }
  }

这可能吗？到目前为止，我所能做的就是这样：

[
  {
    '$project': {
      '_id': 0, 
      'accountFeatures': 1
  }
]

原文

I have a load of documents in mongodb which look something like this:

[
  {
    name: "steve",
    accountFeatures: {word: true, excel: false, powerpoint: true}
  },
  {
    name: "john",
    accountFeatures: {word: false, excel: true, powerpoint: true, notes: true}
  },
  {
    name: "rick",
    accountFeatures: {word: true, excel: false, powerpoint: true}
  }
]

I want to run an aggregation to find out how many of each of the keys in the objects are set to true (there are many more keys in the actual data), so the expected output for the sample data would be:

  {
    "res": {
      "excel": 1,
      "notes": 1,
      "powerpoint": 3,
      "word": 2
    }
  }

Is this possible? So far all I can think to do is this:

[
  {
    '$project': {
      '_id': 0, 
      'accountFeatures': 1
  }
]

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揽清风入怀 2025-02-07 08:39:33

您可以使用$ objectToArray和$ unvind，它将允许我们$ group by the键：

db.collection.aggregate([
  {
    $set: {accountFeatures: {$objectToArray: "$accountFeatures"}}
  },
  {
    $project: {
      accountFeatures: {
        $filter: {
          input: "$accountFeatures",
          as: "item",
          cond: {$eq: ["$item.v", true]}
        }
      }
    }
  },
  {
    $unwind: "$accountFeatures"
  },
  {
    $group: {_id: "$accountFeatures.k", v: {$sum: 1}}
  },
  {
    $group: {_id: 0, data: {$push: {k: "$_id", v: "$v"}}}
  },
  {
    $project: {res: {$arrayToObject: "$data"}, _id: 0}
  }
])

$ objecttoArray提取密钥
$ filter仅保留true ands
$ UNTIND将键与不同文档的键
$ group将计算每个键
格式的结果
游乐场示例

You can use $objectToArray and $unwind which will allow us $group by the keys:

db.collection.aggregate([
  {
    $set: {accountFeatures: {$objectToArray: "$accountFeatures"}}
  },
  {
    $project: {
      accountFeatures: {
        $filter: {
          input: "$accountFeatures",
          as: "item",
          cond: {$eq: ["$item.v", true]}
        }
      }
    }
  },
  {
    $unwind: "$accountFeatures"
  },
  {
    $group: {_id: "$accountFeatures.k", v: {$sum: 1}}
  },
  {
    $group: {_id: 0, data: {$push: {k: "$_id", v: "$v"}}}
  },
  {
    $project: {res: {$arrayToObject: "$data"}, _id: 0}
  }
])