How to query and sort natually in MongoDB?

Question

I have a mongoDBcontaining millions of documents.

I want to query the database and sort the results naturally using a specific field.

From Mongo documentation it seems that only naive sort supported. Is there a way to sort naturally?

Example:

doc 1 _id: "abc10.def"
doc 2 _id: "abc2.def"
doc 3 _id: "abc1.def"

Query: db_collection.find({}).sort({_id: 1})

returns a list by order:

doc3 ("abc1.def")
doc1 ("abc10.def")
doc2 ("abc2.def")

how can I sort to receive the following list?:

doc3 ("abc1.def")
doc2 ("abc2.def")
doc1 ("abc10.def")

@Astro: Can you give more info how to use it? I also found the mongo documentation, but wasn't able to understand how to use it. — NirMH
@Astro $natural returns the documents in the order in which the database refers to them on disk. Please read the question and decide if that's really what OP needs — mickl

mickl mickl · Accepted Answer · 2019-04-16T16:56:11

The problem here is that shorter strings should be returned before longer ones and then you should sort alphabetically strings that have the same length. To do that you need a temporary field length which can be added using $strLenBytes.

db.col.aggregate([
    {
        $addFields: {
            length: { $strLenBytes: "$_id" }
        }
    },
    {
        $sort: {
            length: 1, _id: 1
        }
    },
    {
        $project: {
            length: 0
        }
    }
])

How to query and sort natually in MongoDB?

1 Answers