db.user.aggregate(
{$match:{$and:[{_id:{$gt:20}},{_id:{$lt:65}}]}},
{$group:{_id:"$clazz","最大值":{$max:"$times"}, "编号":{$max:"$_id"},"姓名":{$max:"$name"}}}
).forEach(function(doc){
db.user.find({times:doc.最大值}).forEach(function(doc1){
print(doc1)
});
})
```sql