列出朋友之间最常见的游戏

Question

我刚刚开始学习mongodb，所以我对查询的选择目前还不是很好。 所以我会直接解决这个问题。以下是我的每个用户的文档

{
    id:"14198959",
    user_name:"kikStart2X"
    friends:[
                {
                    friend_id:"1419897878",
                    friend_name:"nitpick",
                    profile_picture:"some image data",
                },
                {
                        friend_id:"14198848418",
                        friend_name:"applePie",
                        profile_picture:"some image data",
                }, //etc
            ],
    games:[
            {
                game_id:"1" , 
                game_name:"Bunny Hop"
            },
            {
               game_id:"2" , 
               game_name:"Racing cars",
            },
          ],
}

现在集合中的所有文档都具有相同的结构

1）friends数组代表我朋友的用户

2）games array代表我玩过的游戏

我的朋友将拥有与包含他们所玩游戏的游戏阵列相同的文档结构

我想要的是以升序/降序或任何顺序列出我和朋友之间最常见的游戏。

结果应如下所示

{
    result:
    [
        {
            game_id:"1" , 
            game_name:"Bunny Hop",
            friends:
            [
                {
                        friend_id:"1419897878",
                        friend_name:"nitpick",
                        profile_picture:"some image data",
                },
                {
                        friend_id:"14198848418",
                        friend_name:"applePie",
                        profile_picture:"some image data",
                },

            ]
        },
        {
            game_id:"2" , 
            game_name:"Racing cars",
            friends:
            [
                {
                        friend_id:"71615343",
                        friend_name:"samuel",
                        profile_picture:"some image data",
                },
            ]
        }
    ]
}

我知道这有点难以实现，但我不知道该怎么做，并在互联网上搜索了几个小时。 在此先感谢所有MongoDB冠军。

Answer 1

您可以尝试以下聚合查询。

对于每个朋友游戏，查询将$unwind friends数组跟进$lookup。

下一步是$unwind friendsgames，然后使用$setIntersection阶段中的$project进行比较，找到输入文档games与每个friendsgames之间的常见游戏{1}}。

最后一步是$group games用friends收集相同游戏的db.collection.aggregate( [ { $unwind:"$friends" }, { $lookup: { from: collectionname, localField: "friends.friend_id", foreignField: "id", as: "friendsgames" } }, { $unwind:"$friendsgames" }, { $project:{commongames:{$setIntersection:["$games", "$friendsgames.games"]}, friends:1 }}, { $unwind:"$commongames" }, { $group:{_id:"$commongames", friends:{$push:"$friends"} } } ] ) 。

document.addEventListener("DOMContentLoaded", function(event) {
        makingRanking();
    });
    
    function makingRanking(){
    	var ranking_groups = document.getElementsByClassName("Ranking");
    	
    	for (var i=0; i < ranking_groups.length; i++){
    		var ranking_items = ranking_groups[i].getElementsByClassName("DemoQuest");
    		
    		for(var j=0; j < ranking_items.length; j++){
    			var id = ranking_items[j].id;
    			ranking_items[j].draggable = true;
    			ranking_items[j].ondragstart = function(){ dragStart(event);}
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    	if (data != ""){
    		if (ev.target.classList.contains("DemoQuest")){
    			temp = ev.target.outerHTML;
    			ev.target.outerHTML = document.getElementById(data).outerHTML;
    			ev.target.draggable = true;
    			ev.target.ondragstart = function(){ dragStart(event);}
    			ev.target.ondrop = function(){ dropHappened(event);}
    			ev.target.ondragover = function(){ dragAndDrop(event);}
    		} else {
    			temp = ev.target.parentElement.outerHTML;
    			ev.target.parentElement.outerHTML = document.getElementById(data).outerHTML;
    			ev.target.parentElement.draggable = true;
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    			ev.target.parentElement.ondrop = function(){ dropHappened(event);}
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    		document.getElementById(data).id = data + '_temp';
    		document.getElementById(data).outerHTML = temp;
    		document.getElementById(data + '_temp').id = data;
    		document.getElementById(data).draggable = true;
    		document.getElementById(data).ondragstart = function(){ dragStart(event);}
    		document.getElementById(data).ondrop = function(){ dropHappened(event);}
    		document.getElementById(data).ondragover = function(){ dragAndDrop(event);}
    	} else {
    		console.log("HOW THE FUCK?");
    		console.log("Dropping on to:  " + ev.target.id);
    	}
    };
    
    function dragAndDrop(ev){
    	ev.preventDefault();
    	//console.log("Passing over:  " + ev.target.children[0].innerHTML);
    };