CODEWITHSUNDEEP
node.jsmongodbsortingmongoose
lightbringer
lightbringer

Reputation: 409

How to sort a mongodb query result in ascending order of age, without a createdAt field? (new to old)

When you do a mongodb query, you normally get the results in descending order of age(old to new). How can I get it in the ascending order?

I know that I can save the createdAt timestamp and do a 

  .sort({createdAt:-1})

on the query to do this, but saving the cretedAt timestamp seperately when the information is already present in _id seems like overkill.

Is there a way to get the results in the ascending order of age (new to old) without using a createdAt timestamp?

Upvotes: 1

Views: 1715

Answers (2)

Amar Thakur
Amar Thakur

Reputation: 11

timestamp is already stored in _id field. So if you want to sort documents from new to old. You can do it in the following way -

sort({_id:-1})

Upvotes: 1

Ashutosh Narang
Ashutosh Narang

Reputation: 425

If you are referring to the natural order which reflects insertion order of documents.

Consider the following query :

db.trees.insert( { _id: 1, name: "oak"} )
db.trees.insert( { _id: 2, name: "chestnut"} )
db.trees.insert( { _id: 3, name: "maple"} )
db.trees.insert( { _id: 4, name: "birch"} )

The following query returns the documents in the natural order :

db.trees.find().sort( { $natural: 1 } )

[
 { "_id" : 1, "name" : "oak"}
 { "_id" : 2, "name" : "chestnut"}
 { "_id" : 3, "name" : "maple"}
 { "_id" : 4, "name" : "birch"}
]

However remove operations free up space which are then taken up by newly inserted documents then, natural order of documents will not reflect insertion order.

Upvotes: 0

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