node.js - Mongoose 在对象展开字段上的聚合查找不起作用

Question

我正在尝试从问题文档中查找，同时显示用户的一些结果。用户模式中有一个名为 QuestionAnswer 且类型为数组的字段。我也取消了数组字段，但只返回问题但回答字段。我做错了什么请指导我。

这是我的用户架构:-

let userSchema =  new Schema({
    name: {
        type: String
        required: true
    }
    phoneNo: {
        type: String
        required: true
    }
    questionAnswer: {
        type: [questionAnswerSchema]
    }
});

这是我的问题AnswerSchema

let questionAnswerSchema = new Schema({
    question: {
        type: Schema.Types.ObjectId,
        ref: 'Question',
        required: true
    },
    answer: {
        type: String,
        required: true
    },
});

我的问题架构:-

let questionFields = new Schema({
    title: {
        type: String,
        required: true,
    },
    questionType: {
        type: String,
        required: true,
    },
    sampleAnswer: {
        type: String,
        required: true,
    }
});

和我的查询:-

let recommendationList = await userModel.aggregate([
    {
       $unwind: {
           path: '$questionAnswer',
           preserveNullAndEmptyArrays: true
       }
    },
    {
        $lookup: {
            from: 'questions',
            localField: 'questionAnswer.question',
            foreignField: '_id',
            as: 'questionAnswer'
        }
    },
])

我想要这样的预期输出

{
    name: 'foo',
    phoneNo: '1234567890'
    questionAnswer: [
        {
            question: {
                title: 'This is the first question'
                questionType: 'longQuestion'
                sampleAnswer: 'this is dummy sample answer'
            }
            answer: 'this is my first actual answer'
        },
        {
            question: {
                title: 'This is the second question'
                questionType: 'shortQuestion'
                sampleAnswer: 'this is dummy sample answer'
            }
            answer: 'this is my second actual answer'
        },

    ]
}

Answer 1

您需要在聚合管道中添加更多过滤器。以下是模型的完整聚合查询。希望对您有帮助!

let recommendationList = await userModel.aggregate([
    {
      $unwind: unwindQuestion
    },
    {
      $lookup: questionLookup
    },
    {
      $unwind: '$datingQuestionAnswer.question'
    },
    {
      $addFields: {
        datingQuestionAnswer: {
          $mergeObjects: ['$datingQuestionAnswer', '$datingQuestionAnswer']
        }
      }
    },
    {
      $group: {
        _id: '$_id',
        datingQuestionAnswer: { $push: '$datingQuestionAnswer' },
      }
    },
    {
      $project: {
        _id: 1,
        datingQuestionAnswer: 1,
        pageNo: 1
      }
    },
])