mongodb 聚合：如果满足条件则排序，否则 return 文档原样

Question

我想编写一个聚合管道，如果条件满足，我想在其中进行排序。如果不满足条件，那么我只想 return 按原样处理文件。如何继续下去？我正在检查 has_presence 字段以决定是否根据名称字段对文档进行排序的示例文档（每个文档将始终有一个 has_presence 字段）：

案例 1：

Input:
    {
    "name": "microsoft",
    "has_presence": true
    },
    {
    "name": "google",
    "has_presence": true
    }
Output:
    {
    "name": "google",
    "has_presence": true
    },
    {
    "name": "microsoft",
    "has_presence": true
    }
Explanation: has_presence is true, so sorted the output by name.

案例 2：

Input:
    {
    "name": "microsoft",
    "has_presence": false
    },
    {
    "name": "google",
    "has_presence": false
    }
Output:
    {
    "name": "microsoft",
    "has_presence": false
    },
    {
    "name": "google",
    "has_presence": false
    }
Explanation: has_presence is false, so kept the order as it is in output.

Answer 1

这是我的例子：https://mongoplayground.net/p/5p7HOws9l5Q

db.collection.aggregate([
  {
    "$project": {
      name: 1,
      has_presence: 1,
      sort: {
        "$cond": {
          "if": "$has_presence",
          "then": "$name",
          "else": "_id"
        }
      }
    }
  },
  {
    $sort: {
      sort: 1
    }
  }
])

mongodb 聚合：如果满足条件则排序，否则 return 文档原样

mongodb aggregation: sort if condition is satisfied else return document as it is

mongodb

pymongo

mongodb-query

aggregation-framework