如何在mongodb中将时间戳转换为日期? [英] how to convert timestamp to date in mongodb?

问题描述

我正在进行mongodb集合的聚合.我的mongodb集合在时间戳中具有creation_time.如何收集当天的结果并与第二天的结果进行聚合?假设我必须收集5天的数据.我的mongodb集合是:

i am working on aggregation of mongodb collection.my mongodb collection has creation_time in timestamp.How will i can collect same day result and aggregate with next day result.Suppose i have to collect data for 5 days.My mongodb collection is:

{
    "_id" : "1522845653126"
},
{
    "_id" : "1522838153324"
},
{
    "_id" : "1513421466415"
},
{
    "_id" : "1515488183153"
},
{
    "_id" : "1521571234500"
}

我该如何计算.在特定日期保存了多少项? nd假设我要查询的结果返回聚合的运行总计，例如:

How can i calculate.How many entry are save on specific date?? nd suppose I want is to query results that returns a running total of the aggregation, like:

{
 time: "2013-10-10"
 count: 3,

},
{
 time: "2013-10-11"
 total: 7,

}

类似的东西. 我试图做这样的事情

something like this. i have tried to do something like this

db.coll.aggregate([
   {
        $group:{
        _id:new Date($creation_time).toLocaleDateString(),
         $count:{$add:1}
            }
         time:new Date($creation_time).toLocaleDateString()
   }
 ])

它不起作用.我在哪里做错了?我是mongodb的新手. 感谢您的帮助

It does not work.where am i doing wrong??I am new to mongodb. Thanks for any help

推荐答案

您可以使用 $toLong 将 mongodb 3.6

You can use $toDate aggregation to convert timestamp to ISO date and $toLong to convert string timestamp to integer value in mongodb 3.6

db.collection.aggregate([
  { "$project": {
    "_id": {
      "$toDate": {
        "$toLong": "$_id"
      }
    }
  }},
  { "$group": {
    "_id": { "$dateToString": { "format": "%Y-%m-%d", "date": "$_id" } },
    "count": { "$sum": 1 }
  }}
])

尝试> 此处

以及以前的版本

db.collection.aggregate([
  { "$project": {
    "date": { "$add": [ new Date(0), "$_id" ] }
  }}
])

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