Mongoose / MongoDB汇总子文档数组的字段

Question

我对MongoDB / Mongoose相当陌生，我不知道应该如何获得想要的结果。 基本上我有一个像这样的文件：

{
    "playerId" : "",
    "sessions" : [ 
        {
            "start" : "",
            "end" : "",
            "join" : "",
            "leave" : "",
            "rounds" : [,
                {
                    "name" : "roundName",
                    "weapons" : [
                        {
                            "name" : "weaponName",
                            "kills" : 1,
                            "assits" : 1,
                            "deaths" : 1,
                            "shots" : 1,
                            "headshots" : 1
                        },
                        {
                            "name" : "weaponName",
                            "kills" : 1,
                            "assits" : 1,
                            "deaths" : 1,
                            "shots" : 1,
                            "headshots" : 1
                        }
                    ]
                },
                {
                    "name" : "roundName",
                    "weapons" : [
                        {
                            "name" : "weaponName",
                            "kills" : 1,
                            "assits" : 1,
                            "deaths" : 1,
                            "shots" : 1,
                            "headshots" : 1
                        },
                        {
                            "name" : "weaponName",
                            "kills" : 1,
                            "assits" : 1,
                            "deaths" : 1,
                            "shots" : 1,
                            "headshots" : 1
                        }
                    ]
                },
                {
                    "name" : "roundName",
                    "weapons" : [
                        {
                            "name" : "weaponName",
                            "kills" : 1,
                            "assits" : 1,
                            "deaths" : 1,
                            "shots" : 1,
                            "headshots" : 1
                        },
                        {
                            "name" : "weaponName",
                            "kills" : 1,
                            "assits" : 1,
                            "deaths" : 1,
                            "shots" : 1,
                            "headshots" : 1
                        }
                    ]
                }
            ]
        }
    ]
}

我想要的是一个查询，该查询在每个回合中添加了包含所有武器总和的字段（杀伤，死亡，助攻，爆头，射门）。 如果可能的话，整个会话也应如此。 任何帮助将不胜感激！

Answer 1

以下应该给您按会话->回合分组的统计信息列表：这里的假设是1）集合的名称是ShootingGame 2）字段的名称是$ sessions.Rounds.Weapons

db.shootingGame.aggregate(
   [
       {$group: {
       _id: "$sessions.Rounds", 
       "sumkills": {$sum: "$sessions.Rounds.Weapons.kills" },
       "sumasists": {$sum: "$sessions.Rounds.Weapons.assists" },
       "sumdeaths": {$sum: "$sessions.Rounds.Weapons.deaths" },
       "sumheadshots": {$sum: "$sessions.Rounds.Weapons.headshots" },
       "sumshots": {$sum: "$sessions.Rounds.Weapons.shots" }
   }}
   ]
)

但是，为了将每个会话进一步分组，您必须将此结果存储到另一个文档中，并每轮运行另一个$ sum组