相关疑难解决方法(0)

我遇到了麻烦(/(ㄒㄒ/)/ ~~).假设集合A是

{ 
    "_id" : ObjectId("582abcd85d2dfa67f44127e1"), 
    "bid" : [
        DBRef("B", ObjectId("582abcd85d2dfa67f44127e0")),
        DBRef("B", ObjectId("582abcd85d2dfa67f44127e1"))
    ]
}

和收藏B:

{ 
    "_id" : ObjectId("582abcd85d2dfa67f44127e0"),  
    "status" : NumberInt(1), 
    "seq" : NumberInt(0)
},
{ 
    "_id" : ObjectId("582abcd85d2dfa67f44127e1"), 
    "status" : NumberInt(1), 
    "seq" : NumberInt(0)
} 

我不知道如何$查找'出价'.我试过了

db.A.aggregate(
    [
        {$unwind: {path: "$bid"}},
        {$lookup: {from: "B", localField: "bid", foreignField: "_id", as: "bs"}},
    ]
) 

和

db.A.aggregate(
    [
        {$unwind: {path: "$bid"}},
        {$lookup: {from: "B", localField: "bid.$id", foreignField: "_id", as: "bs"}},
    ]
)

但它不起作用.有人可以帮忙吗？谢谢.