MongoDB的数组

Question

这里找到值是我收集的模型：

classes:[{ 
      class:String, 
      info:{ 
        subjects:[String], 
        students:[{ 
         name:String, 
         surname:String, 
         matriculae:Number, 
         path_1:String, 
         path_2:String 
        }], 
        classTeacher:{ 
         name:String, 
         surname:String 
        }     
       } 
      }], 
    accademicYear:String}]; 

我想以检索值“matriculae”给学生的名字，姓氏和accademicYear。我无法将我的头裹在身上！感谢帮助。

Answer 1

如果你的意思是你想要的结果扁平格式，试试这个：

School.aggregate([ 
    { 
     $unwind: '$classes' 
    }, { 
     $project: { 
      accademicYear: 1, 
      students: "$classes.info.students" 
     } 
    }, { 
     $unwind: "$students" 
    }, { 
     $project: { 
      accademicYear: 1, 
      matriculae: "$students.matriculae", 
      name: "$students.name", 
      surname: "$students.surname", 
     } 
    } 
    ]) 

在类的情况下收集和accademicYear是collection.Plus添加匹配标准的类里面。

db.getCollection('classes').aggregate([{ 
    $project: { 
     accademicYear: 1, 
     students: "$info.students" 
    } 
}, { 
    $unwind: "$students" 
}, { 
    $project: { 
     accademicYear: 1, 
     matriculae: "$students.matriculae", 
     name: "$students.name", 
     surname: "$students.surname", 
    } 
}, { 
    $match: { 
     name: name, 
     surname: surname, 
     accademicYear: year 

    } 

}])