从 mongo BD 中的 facet 命令获取信息

Question

我正在尝试从管道中提取姓名列表，我得到以下信息：

 command_5 = {"$facet": {
        "list_of_station_names": my_query_1}}

并得到结果：

list_of_station_names  :  [{'desc': 'Sip Ave'}, {'desc': 'Vesey Pl &; River Terrace'}, {'desc': 'Murray St &; West St'},{'desc': 'E 81 St &; York Ave'}]

但我需要列表中没有属性名称“desc”的结果，如下所示：

 list_of_station_names  :  ['Sip Ave', 'Vesey Pl &; River Terrace','Murray St &; West St','E 81 St &; York Ave']

Answer 1

只能映射到facet之后

db.collection.aggregate([
  {
    $facet: {
      list_of_station_names: []
    }
  },
  {
    $set: {
      list_of_station_names: {
        $map: {
          input: "$list_of_station_names",
          as: "n",
          in: "$$n.desc"
        }
      }
    }
  }
])

mongoplayground

从 mongo BD 中的 facet 命令获取信息

Get information from facet command in mongo BD

python

mongodb

pymongo

mongodb-query