关于数组字段的查询问题

x4_965be

假设集合的文档结构如下：

{
   "StudentID":"S0001",
   "Scores":[{"Course":"Chinese","Score":75},{"Course":"Maths","Score":80},{"Course":"English","Score":78}]
}
{
   "StudentID":"S0002",
   "Scores":[{"Course":"Chinese","Score":80},{"Course":"Maths","Score":78},{"Course":"English","Score":75}]
}
{
   "StudentID":"S0001",
   "Scores":[{"Course":"Chinese","Score":78},{"Course":"Maths","Score":75},{"Course":"English","Score":72}]
}

如何查询Score平均值最高的全部文档？上面示例文档有2个最高值

22265

@x4_965be

db.yyy.insertMany([
{
   "StudentID":"S0001",
   "Scores":[{"Course":"Chinese","Score":75},{"Course":"Maths","Score":80},{"Course":"English","Score":78}]
},
{
   "StudentID":"S0002",
   "Scores":[{"Course":"Chinese","Score":80},{"Course":"Maths","Score":78},{"Course":"English","Score":75}]
},
{
   "StudentID":"S0003",
   "Scores":[{"Course":"Chinese","Score":78},{"Course":"Maths","Score":75},{"Course":"English","Score":72}]
}])
db.yyy.aggregate(
   [
     {
       $unwind:"$Scores"
     },
     {
       $group:{
         _id: '$StudentID',
         avg_score: {$avg: '$Scores.Score'}
       }
     },
     {
       $group:{
         _id: '$avg_score',
         StudentID: { $push : "$_id" }
       }
     },
     {$sort: {_id: -1}},
     {$limit: 1},
     {$unwind: '$StudentID'},
     {$project: {_id:0}}
   ]
);