Question

我使用mongodb 4.0.5。我正在使用查找来加入两个集合，外键是位于request_by数组中的字符串值，另一个是 ObjectId

{
 $addFields: {
            convertedId: {
                $toObjectId: "$request_by.userId"
            }
        }
}

我想将外键转换为ObjectId，以便我可以加入它们。但是它说：“在不支持onError值的$ convert中，从数组到objectId的不支持的转换”

我有类似这样的数据：

Simulation collection
    {
        "_id": "8f361e8969948e1c435c06d7",
        "request_by": [{
            "userId": "ae83ccfa592f4963a395263c",
            "iat": 1544801930,
            "exp": 1544819930
        }],
        "status": "finish",
        "start": "2018-12-14T15:39:29.588Z",
        "end": "2018-12-14T16:59:29.538Z",
        "duration": 80,
        "passing_grade": 100,
        "created_at": "2018-12-14T15:39:29.588Z",
        "updated_at": "2018-12-14T15:43:12.897Z",
        "__v": 0
    }

如果我有这样的数据，我该如何加入他们？

Answer 1

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$lookup

Mongodb：不支持从$ convert中的数组到objectId的转换，没有onError值

1 个答案: