MongoDB Query to Find and Sort Documents

Use db.collection.find(query).sort({field: 1}) to find documents matching query and sort them by field in ascending order; use -1 for descending order.

Examples

InputFind all users and sort by age ascending

Output[{ "name": "Anna", "age": 22 }, { "name": "Bob", "age": 30 }, { "name": "Cara", "age": 35 }]

InputFind users with age > 25 and sort by name descending

Output[{ "name": "Cara", "age": 35 }, { "name": "Bob", "age": 30 }]

InputFind users with name 'John' and sort by age ascending

Output[]

How to Think About It

To find and sort documents, first decide what filter you want to apply using find(). Then, use sort() to order the results by one or more fields, specifying 1 for ascending or -1 for descending order.

Algorithm

1

Get the collection to query.

2

Apply the filter criteria using <code>find()</code>.

3

Apply sorting using <code>sort()</code> with the desired field and order.

4

Return the sorted list of documents.

Code

mongodb

db.users.insertMany([
  { name: "Bob", age: 30 },
  { name: "Anna", age: 22 },
  { name: "Cara", age: 35 }
]);

const results = db.users.find({}).sort({ age: 1 }).toArray();
printjson(results);

Output

[
  { "_id": ObjectId("..."), "name": "Anna", "age": 22 },
  { "_id": ObjectId("..."), "name": "Bob", "age": 30 },
  { "_id": ObjectId("..."), "name": "Cara", "age": 35 }
]

Dry Run

Let's trace finding all users and sorting by age ascending.

1

Insert sample users

[{ name: "Bob", age: 30 }, { name: "Anna", age: 22 }, { name: "Cara", age: 35 }]

2

Find all users

Returns all 3 users in any order

3

Sort users by age ascending

Orders users as Anna (22), Bob (30), Cara (35)

Name	Age
Anna	22
Bob	30
Cara	35

Why This Works

Step 1: Find documents

The find() method filters documents matching the query criteria.

Step 2: Sort results

The sort() method orders the matched documents by the specified field and direction.

Step 3: Return sorted list

The final output is the list of documents sorted as requested.

Alternative Approaches

Aggregation pipeline with $match and $sort

mongodb

db.users.aggregate([
  { $match: { age: { $gt: 25 } } },
  { $sort: { name: -1 } }
]).toArray();

More flexible for complex queries but slightly more verbose.

Find with projection and sort

mongodb

db.users.find({}, { name: 1, age: 1, _id: 0 }).sort({ age: -1 }).toArray();

Returns only selected fields with sorting, useful to reduce data size.

Complexity: O(n log n) time, O(n) space

Time Complexity

Sorting requires comparing documents, which takes O(n log n) time for n documents.

Space Complexity

The query stores matched documents in memory before sorting, so space is O(n).

Which Approach is Fastest?

Using find().sort() is efficient for simple queries; aggregation is better for complex filtering and sorting.

Approach	Time	Space	Best For
find().sort()	O(n log n)	O(n)	Simple find and sort
Aggregation pipeline	O(n log n)	O(n)	Complex queries with multiple stages
Find with projection and sort	O(n log n)	O(n)	Reducing returned fields with sorting