从 MongoDB 获取分层嵌套数据

Question

我是 MongoDB 的新手。但是，我对一些aggregate 函数/运算符有所了解。

首先，请看一下数据（它包含板球比赛信息）：

一个文档（行）如下所示：

{
    "ID": 577,
    "Inning": 1,
    "BattingTeam": "Sunrisers Hyderabad",
    "BowlingTeam": "Royal Challengers Bangalore",
    "Over": 1,
    "Bowler": "S Aravind",
    "Ball": 1,
    "Batsman": "DA Warner",
    "NonStriker": "S Dhawan",
    "TotalRuns": 1
}
...
...

这是整个数据文件： http://raw.sam016.com/shared/match_data.json

那些不懂板球的人（比如我），这里有一些信息：

• 一场比赛包含 2 局 [1, 2]
• 每局都有一些过场 [20, 60]
• 每个以上最多包含 6 个球

我想以这种方式聚合/分组这些数据以获得以下类型的分层结果：

[{
    "ID": 577,
    "Innings": [{
            "Inning": 1,
            "BattingTeam": "Sunrisers Hyderabad",
            "BowlingTeam": "Royal Challengers Bangalore",
            "Overs": [
                {
                    "Over": 1,
                    "Bowler": "S Aravind",
                    "Balls": [
                        {
                            "Ball": 1,
                            "Batsman": "DA Warner",
                            "NonStriker": "S Dhawan",
                            "TotalRuns": 1
                        },
                        {...},
                        {...}
                    ]
                },
                {...},
                {...}
            ]
        },
        {
            "Inning": 2,
            "BattingTeam": "Royal Challengers Bangalore",
            "BowlingTeam": "Sunrisers Hyderabad",
            "Overs": [
                {
                    "Over": 1,
                    "Bowler": "B Kumar",
                    "Balls": [
                        {
                            "Ball": 1,
                            "Batsman": "CH Gayle",
                            "NonStriker": "V Kohli",
                            "TotalRuns": 0
                        },
                        {...},
                        {...}
                    ]
                },
                {...},
                {...}
            ]
        }
    ]
}]

我们将不胜感激。

Answer 1

您可以尝试以下聚合管道。

您只需$group 键和$push 数据即可创建每个级别。

从最内层Balls 开始，一直到Innings。

db.cricket.aggregate({
    $group: {
        "_id": {
            "ID": "$ID",
            "Inning": "$Inning",
            "BattingTeam": "$BattingTeam",
            "BowlingTeam": "$BowlingTeam",
            "Over": "$Over",
            "Bowler": "$Bowler"
        },
        "Balls": {
            $push: {
                "Ball": "$Ball",
                "Batsman": "DA Warner",
                "NonStriker": "S Dhawan",
                "TotalRuns": "$TotalRuns"
            }
        }
    }
},
{
    $group: {
        _id: {
            "ID": "$_id.ID",
            "Inning": "$_id.Inning",
            "BattingTeam": "$_id.BattingTeam",
            "BowlingTeam": "$_id.BowlingTeam"
        },
        "Overs": {
            $push: {
                "Over": "$_id.Over",
                "Bowler": "$_id.Bowler",
                "Balls":"$Balls"
            }
        }
    }
},
{
    $group: {
        "_id": "$_id.ID",
        "Innings": {
            $push: {
                "Inning": "$_id.Inning",
                "BattingTeam": "$_id.BattingTeam",
                "BowlingTeam": "$_id.BowlingTeam",
                "Overs":"$Overs"
            }
        }
    }
})