mongdb查询问题？

Question

{

"_id" : 1,
"label" : "1111",
"files" : [ 
    {
        "id" : "aaa",
        "createAt" : 1559803584563.0,
        "updateAt" : 1559803584563.0,
        "status" : 0,
        "annotationsUsers" : []
    }, 
    {
        "id" : "bbb"
        "createAt" : 1561083788761.0,
        "updateAt" : 1561083788761.0,
        "status" : 0,
        "annotationsUsers" : []
    }
]

}

{

"_id" : 2,
"label" : "1111",
"files" : [ 
    {
        "id" : "ccc",
        "createAt" : 1559803584563.0,
        "updateAt" : 1559803584563.0,
        "status" : 0,
        "annotationsUsers" : []
    }, 
    {
        "id" : "ddd"
        "createAt" : 1561083788761.0,
        "updateAt" : 1561083788761.0,
        "status" : 0,
        "annotationsUsers" : []
    }
]

}
这是一个mongodb得文档内容,想查询其中_id为2且files里边id为ccc得内容应该怎么查

 dbo.collection('AnnotationFileGroups').findOne({_id: groupId,"files.id":"ccc"}, {files:{$elemMatch:{id:"ccc"}}},(e, result) => {})

我这样查仍然查到的是_id为2的整个文档应该怎么改？

Answer 1

方法1：根据_id为2获取doc => 得到files => 刷选出_id为ccc的数据。
方法2：files作为一个Collection