mongodb - 选择按字段分组的文档

Question

我有这个显示时间和日期的电影文件:

`{
   "_id": ObjectId("5628668c3e82c49245b7acdc"),
   "ticketID": ObjectId("5606d36b5fbd7d76028b4b08"),
   "uid": "50000",
   "day": "Friday",
   "date": "2015-10-23 21:05:00",
   "adult": NumberLong(550),
   "student": NumberLong(550),
   "children": NumberLong(250),
   "limit": NumberLong(20),
   "sold": NumberLong(0) 
},{
   "_id": ObjectId("562866013e82c49045b7acdc"),
   "ticketID": ObjectId("5606d36b5fbd7d76028b4b08"),
   "uid": "50000",
   "day": "Friday",
   "date": "2015-10-23 19:30:00",
   "adult": NumberLong(1050),
   "student": NumberLong(800),
   "children": NumberLong(550),
   "limit": NumberLong(20),
   "sold": NumberLong(0) 
},{
   "_id": ObjectId("562865013e82c49845b7acda"),
   "ticketID": ObjectId("5606d36b5fbd7d76028b4b08"),
   "uid": "50000",
   "day": "Friday",
   "date": "2015-10-23 18:45:00",
   "adult": NumberLong(1500),
   "student": NumberLong(750),
   "children": NumberLong(750),
   "limit": NumberLong(20),
   "sold": NumberLong(0) 
}
`

我想将最终结果按“天”分组，其中“ticketID”匹配，“日期”作为对象并将“成人”，“学生”，“ child ”，“限制”添加到数组

-- 更新 --

我希望返回的结构如下:

{
  "_id": "ticketID",
  "day": "Friday",
  "items": [
    {
      "date": date,
      "time": time"adult": price,
      "children": price,
      "student": price,
      "limit": value
    },
    {
      "date": date,
      "time": time"adult": price,
      "children": price,
      "student": price,
      "limit": value
    },
    {
      "date": date,
      "time": time"adult": price,
      "children": price,
      "student": price,
      "limit": value
    }
  ]
}

Answer 1

运行以下使用 $group 的聚合管道 运算符按指定字段对文档进行分组，使用累加器运算符添加 items 数组 $push 返回每个组的表达式值数组。 <强> $project 管道运算符(operator)然后通过修改字段来 reshape 文档以获得最终所需的结构:

var pipeline = [
    {
        "$group": {
            "_id": {
                "ticketID": "$ticketID",
                "day": "$day"
            },
            "items": {
                "$push": {
                    "date": "$date",
                    "time": "$time",
                    "adult": "$adult",
                    "children": "$children",
                    "student": "$student",
                    "limit": "$limit"
                }
            }
        }
    },
    {
        "$project": {
            "_id": "$_id.ticketID",
            "day": "$_id.day",
            "items": 1
        }
    }
];

db.collection.aggregate(pipeline);