如何在猫鼬中分组分类

Question

我的数据：

我有category，Sub category 1和sub category2。我通过使用parent_id存储每个类别。这是我的数据

{
    "_id" : ObjectId("000000005e712c388852b550"),
    "__v" : 0,
    "category" : "ewb",
    "created_date" : ISODate("2019-01-09T06:55:57.376Z"),
    "parent_id" : null,
    "status" : "Y",
    "type" : "Column"
}
{
    "_id" : ObjectId("000000005e712c388852b551"),
    "__v" : 0,
    "category" : "wealth",
    "created_date" : ISODate("2019-01-09T06:55:57.378Z"),
    "parent_id" : ObjectId("000000005e712c388852b550"),
    "status" : "Y"
}

{
    "_id" : ObjectId("000000005e712c388852b552"),
    "__v" : 0,
    "category" : "hh economic well-being",
    "created_date" : ISODate("2019-01-09T06:55:57.379Z"),
    "parent_id" : ObjectId("000000005e712c388852b551"),
    "status" : "Y"
}

现在我必须打印为

Category : [{
  category : 'ewb',
  "_id" : ObjectId("000000005e712c388852b550"),
  sub_cat1 : [{
    category : 'wealth',
    "_id" : ObjectId("000000005e712c388852b551"),
    sub_cat2 : [{
      category : 'hh economic well-being',
      "_id" : ObjectId("000000005e712c388852b552"),
      }]
    }]
}]

在不更改架构的情况下如何实现此目的。我指的是