Question

我正在尝试按日期将文档与Mongo聚合框架分组。我尝试了很多东西，无法识别问题。我的查询如下：

// get current date and then get the date 8 months ago
var now = Date.now()
var lastMonth = 60*60*24*30*1000*8
lastMonth = now - lastMonth

var query = {
                type: 'something',
                deleted: {$ne: true},
                created: {$gte: lastMonth}
            }

    var stickerNames = [];
    db.Message.aggregate([{$match: query},
        {$group:
            {_id: {data: '$data',
                    month: {$month: '$created'},
                    year: {$year: '$created'}
                    },
            count:{$sum: 1}
            }
        },
        {$sort:
            {count: 1}}],
        function(err, stuff){
            if(err){
                return res.json({error: err.message})
            }
            else{
                return res.json({data: stuff})
            }
    })

我已经尝试了大量不同的日期和检查其他SO帖子，但到目前为止没有任何工作。如果我取出created：{$ gte：lastMonth}子句，那么它将返回'something'类型的每个文档。如果我离开它，它不会返回任何文件。

创建的字段在模型中按

设置

created: {type: Date, default: Date.now}

Answer 1

据我所知，＆＃34;按日期分组＆＃34;表示分组日期＆＃34;日 - 月 - 年＆＃34;。也许您错过了$dayOfMonth聚合函数？

鉴于此样本数据集：

> db.w.find({})
{ "_id" : ObjectId("55503d31a3d32cf6295ad897"),
  "created" : ISODate("2014-12-08T12:00:00Z"),
  "data" : 1 }
{ "_id" : ObjectId("55503d43a3d32cf6295ad898"),
  "created" : ISODate("2014-12-08T08:00:00Z"),
  "data" : 2 }
{ "_id" : ObjectId("55503d4ba3d32cf6295ad899"),
  "created" : ISODate("2014-12-08T20:00:00Z"),
  "data" : 3 }
{ "_id" : ObjectId("55503d55a3d32cf6295ad89a"),
  "created" : ISODate("2014-12-06T20:00:00Z"),
  "data" : 4 }
{ "_id" : ObjectId("55503d77a3d32cf6295ad89c"),
  "created" : ISODate("2015-12-08T20:00:00Z"),
  "data" : 5 }

那个聚合管道：

> db.w.aggregate([
       {$group:
         {
           _id: 
             {
               day: {$dayOfMonth: "$created"},
               month: {$month: "$created"}, 
               year: {$year: "$created"}
             }, 
             total: {$sum: "$data"},
             count: {$sum: 1}
          }
        },
        {$sort: {count: 1}}
])

您将收到预期的结果：

{ "_id" : { "day" : 8, "month" : 12, "year" : 2015 }, "total" : 5, "count" : 1 }
{ "_id" : { "day" : 6, "month" : 12, "year" : 2014 }, "total" : 4, "count" : 1 }
{ "_id" : { "day" : 8, "month" : 12, "year" : 2014 }, "total" : 6, "count" : 3 }

按日期分组Mongo聚合

1 个答案: