小编mat*_*410的帖子

如果我有以下格式的数据：

[
  {
    _id: 1,
    startDate: ISODate("2017-01-1T00:00:00.000Z"),
    endDate: ISODate("2017-02-25T00:00:00.000Z"),
    type: 'CAR'
  },
  {
    _id: 2,
    startDate: ISODate("2017-02-17T00:00:00.000Z"),
    endDate: ISODate("2017-03-22T00:00:00.000Z"),
    type: 'HGV'
  }
]

是否可以检索按“类型”分组的数据，但也可以检索给定日期范围内每个月的类型计数，例如在 2017/1/1 到 2017/4/1 之间将返回：

[
  {
   _id: 'CAR', 
   monthCounts: [
     /*January*/
     {
       from: ISODate("2017-01-1T00:00:00.000Z"), 
       to: ISODate("2017-01-31T23:59:59.999Z"), 
       count: 1
     },
     /*February*/
     {
       from: ISODate("2017-02-1T00:00:00.000Z"), 
       to: ISODate("2017-02-28T23:59:59.999Z"), 
       count: 1
     },
     /*March*/
     {
       from: ISODate("2017-03-1T00:00:00.000Z"), 
       to: ISODate("2017-03-31T23:59:59.999Z"), 
       count: 0
     },
   ]
  },
  {
   _id: 'HGV', 
   monthCounts: [
     {
       from: ISODate("2017-01-1T00:00:00.000Z"), 
       to: ISODate("2017-01-31T23:59:59.999Z"), 
       count: 0
     },
     {
       from: ISODate("2017-02-1T00:00:00.000Z"), 
       to: …