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This article will introduce various methods of sorting timestamps in MongoDB.

Sorting by timestamp in MongoDB

sort()The method will sort documents in MongoDB. The method accepts a document containing a list of fields and the order in which the fields should be sorted.

1 and -1 specify the sort order. For ascending order, use 1; for descending order, use -1.

grammar:

db.collection_name.find().sort({ field_name : 1 | -1 })

In this case, the collection on which you want to perform the sort is specified by collection_name. The field that needs to be sorted in ASC or DESC order is specified by field_name.

If you do not specify a preferred sort order, the sort() method displays the pages in ascending order. An unstable sort produces different results each time it is applied to the same data set.

Using the index, MongoDB can locate the result of the sort operation. If the index scan cannot determine the sort order, MongoDB will perform a top-k sort algorithm.

Consider the following example to help you better understand the previous idea.

> db.employees.find().sort({ "joining_date" : -1 })

In the above example, we sort the employees based on their Join Date in the Employees collection. The Join Date column tracks the ISO formatted Join Date of the employee.

If you wish to sort based on the created_at field, you can also use _idsince it has a timestamp. This will lead to the same result.

> db.employees.find().sort({ "_id" : -1 })

or

> db.employees.find().sort({ "create_at" : -1 })

Run the above line of code in a MongoShell that is compatible with MongoDB. It will display the following result:

{
  "_id" : ObjectId("54f612b6029b47919a90cesd"),
  "email" : "johndoe@exampledomain.com",
  "name" : "John Doe",
  "create_at" : "ISODate("2020-07-04T00:00:00Z")",
  "joining_date" : "ISODate("2020-07-04T00:00:00Z")"
}
{
  "_id" : ObjectId("54f612b6029b47919a97cesd"),
  "email" : "smithwarn@exampledomain.com",
  "name" : "Smith Warn",
  "create_at" : "ISODate("2020-04-28T00:00:00Z")",
  "joining_date" : "ISODate("2020-04-28T00:00:00Z")"
}
{
  "_id" : ObjectId("54f612b6029b47919a91cesd"),
  "email" : "jessicawill@exampledomain.com",
  "name" : "Jessica Will",
  "create_at" : "ISODate("2019-12-14T00:00:00Z")",
  "joining_date" : "ISODate("2019-12-14T00:00:00Z")"
}