在assignedTo数组中查找分配给成员的所有任务答案

【问题标题】：Find all the tasks assigned to a member inside assignedTo array在assignedTo数组中查找分配给成员的所有任务
【发布时间】：2022-02-07 19:27:15
【问题描述】：

[
 {
  _id: 1,
  title: "Task 1",
  assignedTo: ["userId1", "userId2", "userId3"]
  status: "To do"
 },
 {
  _id: 2,
  title: "Task 2",
  assignedTo: ["userId1", "userId2"],
  status: "In progress"
 },
 {
  _id: 3,
  title: "Task 3",
  assignedTo: ["userId3"],
  status: "Completed"
 }
]

我想使用 MongoDB 聚合来返回分配给用户的所有任务并按状态对它们进行分组。例如，输入是：userId: "userId1"，预期的输出应该是这样的：

{
  results: [
    {
      status: "To do",
      tasks: [
          {
            _id: 1,
            title: "Task 1",
            assignedTo: ["userId1", "userId2", "userId3"]
           }
         ]
    }, 
    {
      status: "In progress",
      tasks: [
          {
            _id: 2,
            title: "Task 2",
            assignedTo: ["userId1", "userId2"]
           }
         ]
    }, 
    {
      status: "Completed",
      tasks: []
    }, 
  ]
}

【问题讨论】：

标签： node.js mongodb aggregate

【解决方案1】：

您可以按status 分组并推送与userId1 匹配的项目

你可以在这里测试mongodb playground

db.collection.aggregate([
  {
    "$group": {
      "_id": {
        status: "$status"
      },
      tasks: {
        "$push": {
          $cond: [
            {
              "$in": [
                "userId1",
                "$assignedTo"
              ]
            },
            {
              _id: "$_id",
              title: "$title",
              assignedTo: "$assignedTo"
            },
            "$$REMOVE"
          ]
        }
      }
    }
  },
  {
    "$project": {
      status: "$_id.status",
      tasks: 1,
      _id: 0
    }
  }
])

【讨论】：