unicloud-db下，如何做"内连接"查询

有个学生成绩表存储了全部学生的成绩，里面有个外键指向学生。我想查询出特定学生的成绩，在unicloud-db的collectionList该如何写呢？

collectionList: [
db.collection("clExamScore").getTemp(),
db.collection("clExam").getTemp(),
db.collection('uni-id-users').where(classTeacherId==$cloudEnv_uid).field("classTeacherId,nickname,_id").getTemp(),
],

这样只能查询出

{
"code": 0,
"errCode": 0,
"message": "",
"errMsg": "",
"systemInfo": [],
"affectedDocs": 4,
"data": [
{
"_id": "6682a8c5a7c432936b69ce4f",
"username": "student",
"yuwen": 100,
"shuxue": 87,
"yingyu": 98,
"wuli": 65,
"huaxue": 96,
"daofa": 54,
"lishi": 94,
"dili": 98,
"shengwu": 95,
"yinyue": 87,
"meishu": 95,
"tiyu": 65,
"exam_id": [
{
"_id": "6682a8c50d2b315faf6f1317",
"name": "期中",
"examYear": 2012,
"examSemester": 1
}
],
"user_id": [
{
"_id": "661fd6e855b3372a1f8638e7",
"nickname": "学生",
"classTeacherId": "66154402fe975f7440cb98e6"
}
]
},
{
"_id": "6682a8c5a7c432936b69ce50",
"username": "student2",
"yuwen": 89,
"shuxue": 88,
"yingyu": 87,
"wuli": 86,
"huaxue": 85,
"daofa": 81,
"lishi": 83,
"dili": 82,
"shengwu": 84,
"yinyue": 84,
"meishu": 84,
"tiyu": 84,
"exam_id": [
{
"_id": "6682a8c50d2b315faf6f1317",
"name": "期中",
"examYear": 2012,
"examSemester": 1
}
],
"user_id": []
},
{
"_id": "6682a8d2a7c432936b69d078",
"username": "student",
"yuwen": 100,
"shuxue": 99,
"yingyu": 98,
"wuli": 97,
"huaxue": 96,
"daofa": 92,
"lishi": 94,
"dili": 93,
"shengwu": 95,
"yinyue": 95,
"meishu": 95,
"tiyu": 95,
"exam_id": [
{
"_id": "6682a8d18a5c7863b168e614",
"name": "期末",
"examYear": 2012,
"examSemester": 1
}
],
"user_id": [
{
"_id": "661fd6e855b3372a1f8638e7",
"nickname": "学生",
"classTeacherId": "66154402fe975f7440cb98e6"
}
]
},
{
"_id": "6682a8d2a7c432936b69d079",
"username": "student2",
"yuwen": 89,
"shuxue": 88,
"yingyu": 87,
"wuli": 86,
"huaxue": 85,
"daofa": 81,
"lishi": 83,
"dili": 82,
"shengwu": 84,
"yinyue": 84,
"meishu": 84,
"tiyu": 84,
"exam_id": [
{
"_id": "6682a8d18a5c7863b168e614",
"name": "期末",
"examYear": 2012,
"examSemester": 1
}
],
"user_id": []
}
],
"count": 4
}