在mongodb中按月份和日期分组并显示列表

Question

我的数据库产品架构结构

{ "_id" :  "507d95d5719dbef170f15bf9" , "name" : "AC3 Series Charger", "type" : "accessory", "price" : 19,"created":"1626083461034"}
{ "_id" :  "507d95d5719dbef170f15bfa" , "name" : "AC3 Case Green", "type" : "case" ,  "price" : 12, "created":"1625805979235"}
{ "_id" :  "507d95d5719dbef170f15bfb" , "name" : "Phone Extended Warranty", "type" : "warranty", "price" : 38,"created":"1624374320653" }
{ "_id" :  "507d95d5719dbef170f15bfc" , "name" : "AC3 Case Black", "type" :  "case" , "price" : 12.5,"created":"1624606153646" }
{ "_id" :  "507d95d5719dbef170f15bfd" , "name" : "AC3 Case Red", "type" : "case" , "price" : 12, "created":"1624362066717"}
{ "_id" :  "507d95d5719dbef170f15bfe" , "name" : "Phone Service Basic Plan", "type" : "service", "price":9.5,"created":"1624446320186"}
{ "_id" :  "507d95d5719dbef170f15bff" , "name" : "Phone Service Core Plan", "type" : "service", "price" :3.5,"created":"1624605403064"}
{ "_id" :  "507d95d5719dbef170f15c00" , "name" : "Phone Service Family Plan", "type" : "service", "price":10.4,"created":"1624446320173"}

我想获取基于 month and day 的记录，为此，我编写了如下查询

db.collection.aggregate([
    { "$group": {
            _id: { month:{ "$month": { "$toDate": "$created" }, day: "$day"  } },
            product: { "$push": "$name" }
    }}
  ])

但它给出了错误

An object representing an expression must have exactly one field: { $month: { $toDate: \"$created\" }, day: \"$day\" }

预期输出

 {
      month:5
      day:12
      products:[
          {
            "name" : "Phone Service Family Plan"
          },
          {"name" : "Phone Service Core Plan"}
      ]
  }

Answer 1

您需要先使用 $toLong 将字符串转换为 long 并使用 $dayOfMonth 运算符，因为 MongoDB 中没有 $day：

db.collection.aggregate([
    {
        "$group": {
            _id: {
                month: { "$month": { "$toDate": { $toLong: "$created" } } },
                day: { "$dayOfMonth": { "$toDate": { $toLong: "$created" } } }
                
            },
            product: {
                "$push": "$name"
                }
            }
    },
    {
        $group: {
            _id: "$_id.month",
            monthDays: {
                $push: {
                    day: "$_id.day",
                    product: "$product"
                }
            }
        }
    },
    {
        $project: {
            _id: 0,
            month: "$_id",
            monthDays: 1
        }
    },
])

Mongo Playground