PROSAGA码农传奇-Mongodb-需要从MongoDB嵌入式集合中计算单个字段数

需要从MongoDB嵌入式集合中计算单个字段数

作者: 12345
发布时间: 2024-08-24 03:51:31 (1月前)
转自：

<div class =“post-text”itemprop =“text”>
  <P>
    尝试以下内容：
  </p>
   <pre>
    <code>
      db.database.aggregate([
    {
       $match: { "_id":ObjectId("5c8a4f4e7c5f002838e61b24") }
    },
    {
        $facet: {
            countOfPrintServices: [
                {
                    $unwind: "$printServiceCategories"
                },
                {
                    $unwind: "$printServiceCategories.groupTypes"
                },
                {
                    $unwind: "$printServiceCategories.groupTypes.printServices"
                },
                {
                    $group: {
                        _id: "$_id",
                        count:{$sum:1}
                    }
                }
            ],
            countOfGrouptypeInPrintServiceCategories : [
                {
                    $unwind: "$printServiceCategories"
                },
                {
                    $unwind: "$printServiceCategories.groupTypes"
                },
                {
                    $group: {
                        _id: "$_id",
                        count:{$sum:1}
                    }
                }
            ],
            countOfPrintServiceCategoriesInProductTemplate: [
                {
                    $unwind: "$printServiceCategories"
                },
                {
                    $group: {
                        _id: "$_id",
                        count:{$sum:1}
                    }
                }
            ]
        }
    }

])

</code>
  </pre>
  <P>
    您可能不会通过优化的解决方案获得所需的结果。
  </p>
   <pre>
    <code>
      {
    "countOfPrintServices" : [
        {
            "_id" : ObjectId("5c58401e354bba286ce4db67"),
            "count" : 5
        }
    ],
    "countOfGrouptypeInPrintServiceCategories" : [
        {
            "_id" : ObjectId("5c58401e354bba286ce4db67"),
            "count" : 2
        }
    ],
    "countOfPrintServiceCategoriesInProductTemplate" : [
        {
            "_id" : ObjectId("5c58401e354bba286ce4db67"),
            "count" : 2
        }
    ]
}

</code>
  </pre>
</DIV>