如何将布尔转换为字符串&；按聚合管道中的条件更改值-MongoDB_Mongodb_Mongodb Query_Aggregation Framework

如何将布尔转换为字符串&；按聚合管道中的条件更改值-MongoDB

mongodb

如何将布尔转换为字符串&；按聚合管道中的条件更改值-MongoDB,mongodb,mongodb-query,aggregation-framework,Mongodb,Mongodb Query,Aggregation Framework,有记录的集合，需要将列的布尔值转换为字符串： [ { _id: "bmasndvhjbcw", name: "lucas", occupation: "scientist", passed_phd: true, age: 55, location: "texas", }, { _id: "bmasndvhjbcx", name: "mark", occupation: "scientist", age:

有记录的集合，需要将列的布尔值转换为字符串：

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

如何将记录的布尔值更改为字符串

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

传递的参数中为true（布尔）的值应转换为“是”（字符串）

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

传递的phd中包含false（布尔值）的值应转换为“否”（字符串）

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

mongodb版本4.0

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

尝试过这个：

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]


{passed_phd : [{'passed_phd':true},{$set:{'passed_phd':"yes"}] }

Expected "[" or AggregationStage but "{" found.

错误：

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]


{passed_phd : [{'passed_phd':true},{$set:{'passed_phd':"yes"}] }

Expected "[" or AggregationStage but "{" found.

您需要使用转换为字符串和条件运算符来更改字段值，请尝试将以下阶段添加到聚合管道：

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

{
    $addFields: {
      passed_phd: {
        $switch: {
          branches: [
            {
              case: {
                $eq: [
                  "$passed_phd",
                  true
                ]
              },
              then: "yes"
            },
            {
              case: {
                $eq: [
                  "$passed_phd",
                  false
                ]
              },
              then: "no"
            },

          ],
          default: {
            $toString: "$passed_phd"
          }
        }
      }
    }
  }

测试：

[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

如果字段存在，则无需使用

$switch

，因为

已通过的字段只能有两个值，所以只需使用$cond
运算符：
[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

{
    $addFields: {
      passed_phd: {
        $cond: [
          {
            $eq: [
              "$passed_phd",
              true
            ]
          },
          "yes",
          "no"
        ]
      }
    }
  }

测试：
您需要使用转换为字符串和条件运算符来更改字段值，请尝试将以下阶段添加到聚合管道中：
[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

{
    $addFields: {
      passed_phd: {
        $switch: {
          branches: [
            {
              case: {
                $eq: [
                  "$passed_phd",
                  true
                ]
              },
              then: "yes"
            },
            {
              case: {
                $eq: [
                  "$passed_phd",
                  false
                ]
              },
              then: "no"
            },

          ],
          default: {
            $toString: "$passed_phd"
          }
        }
      }
    }
  }

测试：
[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

如果字段存在，则无需使用$switch
，因为已通过的字段只能有两个值，所以只需使用$cond
运算符：
[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]

{
    $addFields: {
      passed_phd: {
        $cond: [
          {
            $eq: [
              "$passed_phd",
              true
            ]
          },
          "yes",
          "no"
        ]
      }
    }
  }

测试：
您必须使用$project
或addFields
阶段，并使用$cond
或$switch
运算符转换值。另外，请发布到目前为止您尝试过的聚合查询。尝试此{passed_phd:[{'passed_phd'：true}，{$set:{'passed_phd'：“yes”}
在聚合管道中，您必须使用$project
或addFields
阶段，并使用$cond
或$switch
运算符来转换值。此外，请发布您迄今为止尝试过的聚合查询。尝试此{passed_phd:[{'passed_phd'：true}，{$set:{'passed_phd'：“yes”}
在聚合管线中更改字段值？从true更改为yes，从false更改为no@vebey74412：除了true或false
之外，您是否碰巧在passed\u phd
字段中还有其他值？或者是否有任何文档没有passed\u phd
字段？只有true和false存在，每一列都有true或falseE字段值的更改？从真到是，从假到no@vebey74412：除了true或false
，您是否碰巧在passed\u phd
字段中有任何其他值？或者是否存在没有passed\u phd字段的文档？只有true和false存在，每一列都有true或false
[
  {
    _id: "bmasndvhjbcw",
    name: "lucas",
    occupation: "scientist",
    passed_phd: true,
    age: 55,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcx",
    name: "mark",
    occupation: "scientist",
    age: 45,
    passed_phd: true,
    location: "texas",

  },
  {
    _id: "bmasndvhjbca",
    name: "stuart",
    occupation: "lab assistant",
    age: 25,
    passed_phd: false,
    location: "texas",

  },
  {
    _id: "bmasndvhjbcq",
    name: "cooper",
    occupation: "physicist",
    age: 69,
    passed_phd: false,
    location: "texas"
  }
]