MongoDB provides a few ways to sort documents in a particular order. Each of these allow us to order the documents in ascending or descending order.

There’s also the option to order the results of a $text search – sorting by the computed textScore metadata in descending order.

Here are 3 ways to sort documents in MongoDB.

The cursor.sort() Method

The cursor.sort() method specifies the order in which the query returns matching documents.

Suppose we have a collection called employees with the following documents:

{ "_id" : 1, "name" : "Bob", "salary" : 55000 }
{ "_id" : 2, "name" : "Sarah", "salary" : 128000 }
{ "_id" : 3, "name" : "Fritz", "salary" : 25000 }
{ "_id" : 4, "name" : "Christopher", "salary" : 45000 }
{ "_id" : 5, "name" : "Beck", "salary" : 82000 }
{ "_id" : 6, "name" : "Homer", "salary" : 1 }
{ "_id" : 7, "name" : "Bartholomew", "salary" : 1582000 }
{ "_id" : 8, "name" : "Zoro", "salary" : 300000 }
{ "_id" : 9, "name" : "Xena", "salary" : 382000 }

Here’s an example of returning those documents sorted by their salary field in ascending order, and also their _id field:

db.employees.find().sort( { salary: 1, _id: 1 } )

Result:

{ "_id" : 6, "name" : "Homer", "salary" : 1 }
{ "_id" : 3, "name" : "Fritz", "salary" : 25000 }
{ "_id" : 4, "name" : "Christopher", "salary" : 45000 }
{ "_id" : 1, "name" : "Bob", "salary" : 55000 }
{ "_id" : 5, "name" : "Beck", "salary" : 82000 }
{ "_id" : 2, "name" : "Sarah", "salary" : 128000 }
{ "_id" : 8, "name" : "Zoro", "salary" : 300000 }
{ "_id" : 9, "name" : "Xena", "salary" : 382000 }
{ "_id" : 7, "name" : "Bartholomew", "salary" : 1582000 }

Here, we used 1 for ascending order. If we wanted it in descending order, we’d simply use -1 instead.

The reason I included the _id field in the ordering is because, if two or more employees have the same salary, then the _id field can be used to sort those documents between themselves.

While this may seem trivial, it will prevent MongoDB from returning those documents in a different order each time we run the query.

You can also sort the results of a $text search. See MongoDB sort() for an example.

The $sort Aggregation Pipeline Stage

When using the aggregation pipeline framework, you can use the $sort stage to sort all input documents and returns them to the pipeline in sorted order.

Here’s how we can use $sort to return the same result as the previous example. Except, let’s sort them in descending order this time:

db.employees.aggregate(
   [
     { $sort : { salary : -1, _id: 1 } }
   ]
)

Result:

{ "_id" : 7, "name" : "Bartholomew", "salary" : 1582000 }
{ "_id" : 9, "name" : "Xena", "salary" : 382000 }
{ "_id" : 8, "name" : "Zoro", "salary" : 300000 }
{ "_id" : 2, "name" : "Sarah", "salary" : 128000 }
{ "_id" : 5, "name" : "Beck", "salary" : 82000 }
{ "_id" : 1, "name" : "Bob", "salary" : 55000 }
{ "_id" : 4, "name" : "Christopher", "salary" : 45000 }
{ "_id" : 3, "name" : "Fritz", "salary" : 25000 }
{ "_id" : 6, "name" : "Homer", "salary" : 1 }

You can also sort the results of a $text search. See MongoDB $sort for an example.

The $orderBy Query Modifier

The $orderBy query modifier can be used in one of two forms.

Like this:

db.employees.find( { $query: {}, $orderBy: { salary: 1 } } )

Or like this::

db.employees.find()._addSpecial( "$orderby", { salary : 1 } )

The $orderBy query modifier has been deprecated in the mongo shell since v3.2, but I decided to include it here anyway. See the MongoDB documentation for more information.