Mongoose - 具有聚合结果的foreach循环-Java 学习之路

我正在使用带有mongoose插件的node.js来构建具有任务的简单应用程序 . 我的mongoDB架构如下所示：

var userSchema = mongoose.Schema({

    username: String,
    email  : String,
    password : String,
    tasks: [{
      title: String,
      description: String,
      date: {type: Array, "default":[]}, 
      currentPeriod: Number,  
      periodQuantity: Number,
      done: Boolean
    }]

});

我想要做的是（例如）获取任务，其中“done”变量设置为true，并且是一个用户（同一文档）的一部分 . 目前，我的查询如下所示：

User.aggregate({$match:{'email':req.user.email}},{$unwind:"$tasks"},{$match:{'tasks.done':true}},{$project:{'tasks':1,'_id':0}}, function(err,tasks){
      if (err) {
        console.log('Something went wrong during getting inactive task(s) for user "' + req.user.email + '": ' + err);
        res.send(err);
      }
      console.log('Succesfully got ' + tasks.length + ' inactive task(s) for user: "' + req.user.email + '".');
      res.json(tasks);
    });

问题是这种查询的结果是这样的

[
    {"tasks":{"_id":"57372ef07329d9d8f2921ede","title":"Done1","description":"Done1Desc","currentPeriod":3,"periodQuantity":3,"done":true}},
    {"tasks":{"_id":"57372ef07329d9d8f2921edf","title":"Done2","description":"Done2Desc","currentPeriod":11,"periodQuantity":11,"done":true}},
    {"tasks":{"_id":"57372ef07329d9d8f2921ee3","title":"Done3","description":"Done3Desc","currentPeriod":3,"periodQuantity":3,"done":true}},
    {"tasks":{"_id":"57372ef07329d9d8f2921ee4","title":"Done4","description":"Done4Desc","currentPeriod":4,"periodQuantity":4,"done":true}}
    ]

虽然我只想要“属性”任务的值 . 我设法得到了我感兴趣的mongo控制台使用的结果

> var results = [];
> db.users.aggregate({$match:{'email':'admin'}},{$unwind:"$tasks"},{$match:{'tasks.done':true}},{$project:{'tasks':1,'_id':0}}).forEach(function(u) {results.push(u.tasks)})
> results
[
        {
                "_id" : ObjectId("57372ef07329d9d8f2921ede"),
                "title" : "Done1",
                "description" : "Done1Desc",
                "currentPeriod" : 3,
                "periodQuantity" : 3,
                "done" : true
        },
        {
                "_id" : ObjectId("57372ef07329d9d8f2921edf"),
                "title" : "Done2",
                "description" : "Done2Desc",
                "currentPeriod" : 11,
                "periodQuantity" : 11,
                "done" : true
        },
        {
                "_id" : ObjectId("57372ef07329d9d8f2921ee3"),
                "title" : "Done3",
                "description" : "Done3Desc",
                "currentPeriod" : 3,
                "periodQuantity" : 3,
                "done" : true
        },
        {
                "_id" : ObjectId("57372ef07329d9d8f2921ee4"),
                "title" : "Done4",
                "description" : "Done4Desc",
                "currentPeriod" : 4,
                "periodQuantity" : 4,
                "done" : true
        }
]
>

我尝试使用foreach和每个函数在第二个代码片段的末尾，但是当我这样做时，我收到一个错误

TypeError: User.aggregate(...).forEach is not a function

1 回答

这可以使用$group在聚合查询中完成 . 检查以下查询：

db.users.aggregate.aggregate([{
    $unwind: '$tasks'
}, {
    $match: {
        email: req.user.email,
        'tasks.done': true
    }
}, {
    $group: {
        _id: null,
        tasks: {
            $push: '$tasks'
        }
    }
}]);

回复于 2024-04-26T16:37:04+08:00

Mongoose - 具有聚合结果的foreach循环

1 回答

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