Mongodb 如何在mongoose中聚合嵌套查找数组？_Mongodb_Mongoose_Aggregation Framework

Mongodb 如何在mongoose中聚合嵌套查找数组？

mongodb mongoose

Mongodb 如何在mongoose中聚合嵌套查找数组？,mongodb,mongoose,aggregation-framework,Mongodb,Mongoose,Aggregation Framework,我有一个如何查找嵌套数组的问题，例如，我有4个集合用户集合语言集合工作提交收藏我的查询聚合是： db.cvsubmit.aggregate([ { $lookup: { from: "user", localField: "id_user", foreignField: "_id", as: "id_user" } }, {

我有一个如何查找嵌套数组的问题，例如，我有4个集合

用户集合

语言集合

工作

提交收藏

我的查询聚合是：

db.cvsubmit.aggregate([
  {
    $lookup: {
      from: "user",
      localField: "id_user",
      foreignField: "_id",
      as: "id_user"
    }
  },
  {
    $lookup: {
      from: "language",
      localField: "id_user.language.language_id",
      foreignField: "_id",
      as: "id_user.language.language_id"
    }
  },
])

但结果是：

[
  {
    "_id": "11",
    "id_job": "11",
    "id_user": {
      "language": {
        "language_id": [
          {
            "_id": "919",
            "name": "English"
          },
          {
            "_id": "920",
            "name": "Chinese"
          }
        ]
      }
    }
  }
]

我想要这样的结果，同时显示所有用户数据细节，如

name

：

[
  {
    "_id": "11",
    "id_job": "11",
    "id_user": {
      "_id": "1234",
      "name": "Tony"
      "language": [
          {
            "_id": "919",
            "name": "English",
            "Level": "Expert"
          },
          {
            "_id": "920",
            "name": "Chinese",
            "level": "Basic"
          }
        ]
    }
  }
]

Mongo游乐场连接线

之前谢谢。

```
$lookup
```
与
```
用户
```
集合
```
$unwind
```
解构
```
id\u用户
```
数组
```
$lookup
```
使用
```
语言
```
收集并返回
```
语言
```
字段
```
$map
```
迭代
```
id\u user.language
```
数组的外观

$reduce

要迭代从集合返回的

语言

数组的循环，请检查条件

语言id是否匹配，然后返回名称



根据NoSQL，您的数据库结构不准确，最多应该有2个集合，使用$lookup和$unwind进行连接掠夺将导致性能问题
"cvsubmit": [
    {
      "_id": "11",
      "id_user": "1234",
      "id_job": "11"
    }
  ]

db.cvsubmit.aggregate([
  {
    $lookup: {
      from: "user",
      localField: "id_user",
      foreignField: "_id",
      as: "id_user"
    }
  },
  {
    $lookup: {
      from: "language",
      localField: "id_user.language.language_id",
      foreignField: "_id",
      as: "id_user.language.language_id"
    }
  },
])

[
  {
    "_id": "11",
    "id_job": "11",
    "id_user": {
      "language": {
        "language_id": [
          {
            "_id": "919",
            "name": "English"
          },
          {
            "_id": "920",
            "name": "Chinese"
          }
        ]
      }
    }
  }
]

[
  {
    "_id": "11",
    "id_job": "11",
    "id_user": {
      "_id": "1234",
      "name": "Tony"
      "language": [
          {
            "_id": "919",
            "name": "English",
            "Level": "Expert"
          },
          {
            "_id": "920",
            "name": "Chinese",
            "level": "Basic"
          }
        ]
    }
  }
]

db.cvsubmit.aggregate([
  {
    $lookup: {
      from: "user",
      localField: "id_user",
      foreignField: "_id",
      as: "id_user"
    }
  },
  { $unwind: "$id_user" },
  {
    $lookup: {
      from: "language",
      localField: "id_user.language.language_id",
      foreignField: "_id",
      as: "languages"
    }
  },
  {
    $addFields: {
      languages: "$$REMOVE",
      "id_user.language": {
        $map: {
          input: "$id_user.language",
          as: "l",
          in: {
            _id: "$$l._id",
            level: "$$l.level",
            name: {
              $reduce: {
                input: "$languages",
                initialValue: "",
                in: {
                  $cond: [
                    { $eq: ["$$this._id", "$$l.language_id"] },
                    "$$this.name",
                    "$$value"
                  ]
                }
              }
            }
          }
        }
      }
    }
  }
])