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Question

我使用Node JS，Express和MongoDB来创建API，对于这个API，我需要从两个集合中获取数据并发送组合响应，但我无法在最终响应中获取所需数据

router.get('/', function (req, res, next) {
    tno= req.param("tno");

    new_json = {}
 MongoClient.connect(mongoUrl, function (err, db) {

            var cursor = db.collection('tns').find({"tno": tno});


            cursor.toArray(function (err, docs) {
                if (err) {
                    res.json({"error_server": "Error Occured,Please Try Again"})
                }

                mongoose.connect(mongoUrl);

                console.log(tno)
                var Rating = mongoose.model('Rating', ratingSchema);
                Rating.aggregate(
                    [   
                        {
                            $match: {"tno":tno}
                        },
                        {
                            "$group": {
                                "_id": "$tno",
                                "fr": { "$avg": "$fr" },
                                "cr": { "$avg": "$cr" },
                                "pr": { "$avg": "$pr" },
                                "tr": { "$avg": "$tr" },

                            }
                        }
                    ],
                    function(err,results) {
                        if (err) throw err;
                        console.log("INSIDE AGG RESULTS")
                        temp_data=docs
                        console.log(results)
                        temp_data["ratings"]=results
                        console.log(temp_data)
                        res.json(temp_data)


                    }
                );

            });
        }
 });

我能够独立执行这两个查询但不能合并结果