Question

我对猫鼬聚合非常陌生，并且具有以下格式的集合

托收文件：

{
  "movie":"Fast and Furious",
  "rating":"Good",
  "ratingTime":"2015-3-06 4:05:10"
},
{
  "movie":"Avengers Infinity Stones",
  "rating":"Very Good",
  "ratingTime":"2020-20-4 22:10:40"
},
{
  "movie":"Mad Max Fury Road",
  "rating":"Average",
  "ratingTime":"2015-3-06 15:23:25"
},
{
  "movie":"Toy story",
  "rating":"Good",
  "ratingTime":"2020-20-4 10:11:02"
}

我想要下面的格式：

[
   {
       "2015-3-06":[{
            "movie":"Fast and Furious",
            "rating":"Good",
            "ratingTime":"2015-3-06 4:05:10"
        },{
            "movie":"Mad Max Fury Road",
            "rating":"Average",
            "ratingTime":"2015-3-06 15:23:25"
        }]
   },
   {
        "2020-20-4":[{
            "movie":"Avengers Infinity Stones",
            "rating":"Very Good",
            "ratingTime":"2020-20-4 22:10:40"
        },{
            "movie":"Toy story",
            "rating":"Good",
            "ratingTime":"2020-20-4 10:11:02"
        }]
   }
]

有人可以帮助我吗，因为我没有任何想法来获取所需格式的输出。非常感谢您的帮助

Answer 1

根据您的情况，据我了解，您想使用动态模式键。但是我认为这不是一个好主意，最好使用第一个选项并按日期对它们进行排序，或者，如果您真的想使用它，则可以使用{string: false}。使用 strict 可以使您的整个模式为自由格式，如果您不想使整个模式为自由格式，而是希望其中的一部分，则还可以修改您的模式以使用 mixed

   var movieSchema=newSchema({
       movie:{
          type:String
       },
       rating:{
          type:String
       },
       ratingTime:{
          type:Date,
          default:Date.now()
       }
  })

// var movieSchemaByDate = new Schema({..}, { strict: false }); /*if you are using older versions */
    var movieSchemaByDate = new Schema({..}) 
    var Movie = mongoose.model('Movie', movieSchemaByDate);
    var movie = new Movie({ [date]: movieSchema });
    movie.save();

参考：

mongoose strict

Classify mongoose schema arrays by date

Answer 2

我对您的问题的解决方案将是以下类型：

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var movieSchema=newSchema(
{
    movie:{
        type:String
    },
    rating:{
        type:String
    },
    ratingTime:{
        type:Date,
        default:Date.now()
    }
}
)

var yearSchema = new Schema({
    movieYear:[movieSchema]
});
var books=mongoose.model('books',bookSchema)
module.exports=books;

您可以了解有关Mongoose Subdocuments 和Mongoose Schemas的更多信息。

Answer 3

    const aggregate = await Test.aggregate([
      {
        $group: {
          _id: {
            $dateToString: {
              format: '%Y-%m-%d',
              date: '$ratingTime'
            }
          },
          root: {
            $addToSet: '$$ROOT'
          }
        }
      },
      {
        $unwind: {
          path: '$root',
          preserveNullAndEmptyArrays: false
        }
      },
      {
        $group: {
          _id: '$_id',
          movies: {
            $addToSet: '$root'
          }
        }
      }
    ]);
    aggregate.forEach((dateObj) => {
      dateObj[dateObj._id] = dateObj.movies;
      delete dateObj._id;
      delete dateObj.movies;
    });
    console.log(JSON.stringify(aggregate, undefined, 3));

并且由于无法进行动态字段命名（至少我这样认为），因此您需要在获得结果后再进行其余操作。

输出将是：

    [
      {
        '2015-07-03': [
          {
            _id: '5f0a11833456a62a2a91e36a',
            movie: 'Mad Max Fury Road',
            rating: 'Average',
            ratingTime: '2015-07-03T12:23:25.000Z',
            __v: 0
          },
          {
            _id: '5f0a11833456a62a2a91e368',
            movie: 'Fast and Furious',
            rating: 'Good',
            ratingTime: '2015-07-03T12:23:25.000Z',
            __v: 0
          }
        ]
      },
      {
        '2020-05-20': [
          {
            _id: '5f0a11833456a62a2a91e36b',
            movie: 'Toy story',
            rating: 'Good',
            ratingTime: '2020-05-20T07:11:02.000Z',
            __v: 0
          },
          {
            _id: '5f0a11833456a62a2a91e369',
            movie: 'Avengers Infinity Stones',
            rating: 'Very Good',
            ratingTime: '2020-05-20T19:10:40.000Z',
            __v: 0
          }
        ]
      }
    ];

和链接以查看 group by dates in mongodb

https://www.mongodb.com/products/compass

Answer 4

正如答案之一Eric Asca所述，无法进行动态字段命名。您可以按日期将文档分组。有一件事情要注意，给定数据中的日期格式似乎无效，这就是为什么我使用$substr。

const result = await Model.aggregate([
    {
        $group: {
            _id: { $substr: ["$ratingTime", 0, 9] },
            movies: {
                $push: "$$ROOT",
            },
        },
    },
]);

结果看起来像这样。

[
  {
    "_id": "2020-20-4",
    "movies": [
      {
        "_id": "5f0a27a5df68ee25952ae10a",
        "movie": "Avengers Infinity Stones",
        "rating": "Very Good",
        "ratingTime": "2020-20-4 22:10:40",
        "__v": 0
      },
      {
        "_id": "5f0a27a5df68ee25952ae10c",
        "movie": "Toy story",
        "rating": "Good",
        "ratingTime": "2020-20-4 10:11:02",
        "__v": 0
      }
    ]
  },
  {
    "_id": "2015-3-06",
    "movies": [
      {
        "_id": "5f0a27a5df68ee25952ae109",
        "movie": "Fast and Furious",
        "rating": "Good",
        "ratingTime": "2015-3-06 4:05:10",
        "__v": 0
      },
      {
        "_id": "5f0a27a5df68ee25952ae10b",
        "movie": "Mad Max Fury Road",
        "rating": "Average",
        "ratingTime": "2015-3-06 15:23:25",
        "__v": 0
      }
    ]
  }
]

可以轻松将其转换为所需的格式。

const output = result.map(({_id, movies}) => ({[_id]: movies}))

猫鼬查询按日期分组

4 个答案: