从主集合的一个数组中查询在mongo中加入两个集合

Question

我有两个集合，一个是以下子段：

[
  {
    "_id": "5c8b2931ff2fa8129c8f666f",
    "segments": [
      "5c8b2915ff2fa8129c8f666d"
    ],
    "isSchool": false,
    "isActive": false,
    "isDeleted": true,
    "name": "X-IIT MAINS-1552623928407",
    "bannerUrl": "",
    "timestamp": 1552623921559,
    "updatedAt": "2019-03-15T04:25:28.408Z",
    "createdAt": "2019-03-15T04:25:21.559Z",
    "__v": 0,
    "iconUrl": null,
    "updatedById": null
  }
]

其他是细分如下：

[
  {
    "_id": "5a11620dbed7fd0c58ef4ec7",
    "createdAt": "2017-11-19T10:50:53.495Z",
    "updatedAt": "2018-08-27T12:25:36.997Z",
    "timestamp": 1511088653495,
    "bannerUrl": "",
    "iconUrl": "https://bloom-foundation-dev.s3.amazonaws.com/20171129T000000Z_CBSE_Logo-1.jpg",
    "name": "CBSE",
    "isDeleted": false,
    "isActive": true,
    "isSchool": true,
    "__v": 0,
    "updatedById": null
  }
]

我想查询选择子段并将子段的细分数组中各个细分ID的细分详细信息加入