如何MongoDB中对数组进行$lookup连表，将连接获得的数据放入添加到数组

  • Z时代
  • 2024-02-25
  • 分类：IT

我将二级+评论放入一级评论的comment字段中,前端渲染比较方便。

简化版

    "_id" : ObjectId("624a5b8db5dbe4270038527c"),
    "thumbsUp" : [ ],
    "cover" : "\\uploads\\1646753148474.jpg",
    "articleId" : "622c6a8dd48a854b6c9c5f58",
    "userId" : "61f53a222c6dd92ac0881f5e",
    "comment" : [
        {
            "articleId" : "622c6a8dd48a854b6c9c5f58",
            "commentId" : "624a5b8db5dbe4270038527c",
            "parentId" : "61f53a222c6dd92ac0881f5e",
            "userId" : "620fbf1e0c1b451028758e03",
            "value" : "<p>回复你哦</p>\n",
        },
        {
            "articleId" : "622c6a8dd48a854b6c9c5f58",
            "commentId" : "624a5b8db5dbe4270038527c",
            "parentId" : "61f53a222c6dd92ac0881f5e",
            "parentName" : "大聪明",
            "userId" : "61f53a222c6dd92ac0881f5e",
            "value" : "<p>对话1</p>\n",
        },

我通过$lookup可以获取每一已连接用户表的数据
但并不是我想要的数据

db.article.aggregate([
    {
        "$project":
        {
            "userId":
            {
                "$convert": {
                    "input": "$userId",
                    "to": "objectId"
                }
            },
            'title': 1,
            'content': 1,
            'author': 1,
            'type': 1,
            'tag': 1,
            'username': 1,
            'publishDate': 1,
            'comment': 1,
            'cover': 1,
        },
    }, {
        $lookup: {
            from: 'user',
            localField: 'userId',
            foreignField: '_id',
            as: 'user'
        }
    }
])

如何MongoDB中对数组进行$lookup连表，将连接获得的数据放入添加到数组

我希望得到这种数据

  "_id" : ObjectId("624a5b8db5dbe4270038527c"),
    "thumbsUp" : [ ],
    "cover" : "\\uploads\\1646753148474.jpg",
    "articleId" : "622c6a8dd48a854b6c9c5f58",
    "userId" : "61f53a222c6dd92ac0881f5e",
    "comment" : [
        {
            "articleId" : "622c6a8dd48a854b6c9c5f58",
            "commentId" : "624a5b8db5dbe4270038527c",
            "parentId" : "61f53a222c6dd92ac0881f5e",
            "userId" : "620fbf1e0c1b451028758e03",
            "value" : "<p>回复你哦</p>\n",
            //连接用户表
            "username":"123",
            "cover":'1.jpg'
        },
        {
            "articleId" : "622c6a8dd48a854b6c9c5f58",
            "commentId" : "624a5b8db5dbe4270038527c",
            "parentId" : "61f53a222c6dd92ac0881f5e",
            "parentName" : "大聪明",
            "userId" : "61f53a222c6dd92ac0881f5e",
            "value" : "<p>对话1</p>\n",
            //连接用户表
            "username":"223",
            "cover":'2.jpg'
        },

请教各位前辈，谢谢

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