How to Find Documents in MongoDB: Syntax and Examples

To find documents in MongoDB, use the find() method on a collection. You can pass a query object to specify criteria, or leave it empty to get all documents.

Syntax

The find() method is used on a MongoDB collection to retrieve documents. It accepts a query object to filter results and returns a cursor to iterate over matching documents.

• db.collection.find(query, projection)
• query: An object specifying search criteria (empty object {} means no filter).
• projection: Optional object to specify which fields to include or exclude.

mongodb

db.collection.find(query, projection)

Example

This example shows how to find all documents in the users collection and then find documents where the age is greater than 25.

mongodb

use testdb

// Insert sample documents
db.users.insertMany([
  { name: "Alice", age: 30 },
  { name: "Bob", age: 22 },
  { name: "Charlie", age: 28 }
])

// Find all documents
const allUsers = db.users.find({}).toArray()
printjson(allUsers)

// Find users with age > 25
const olderUsers = db.users.find({ age: { $gt: 25 } }).toArray()
printjson(olderUsers)

Output

[
  { "_id": ObjectId("..."), "name": "Alice", "age": 30 },
  { "_id": ObjectId("..."), "name": "Bob", "age": 22 },
  { "_id": ObjectId("..."), "name": "Charlie", "age": 28 }
]
[
  { "_id": ObjectId("..."), "name": "Alice", "age": 30 },
  { "_id": ObjectId("..."), "name": "Charlie", "age": 28 }
]

Common Pitfalls

Common mistakes when using find() include:

• Forgetting to convert the cursor to an array or iterate it, so no results appear.
• Using incorrect query syntax, like missing curly braces or wrong operators.
• Expecting find() to return a single document instead of a cursor (use findOne() for one document).

mongodb

// Wrong: expecting find() to return a document directly
const user = db.users.find({ name: "Alice" })
printjson(user) // prints a cursor object, not the document

// Right: convert cursor to array or use findOne()
const userArray = db.users.find({ name: "Alice" }).toArray()
printjson(userArray)

const singleUser = db.users.findOne({ name: "Alice" })
printjson(singleUser)

Output

Cursor object printed (not useful)
[
  { "_id": ObjectId("..."), "name": "Alice", "age": 30 }
]
{ "_id": ObjectId("..."), "name": "Alice", "age": 30 }

Quick Reference

Command	Description
db.collection.find({})	Find all documents in the collection
db.collection.find({ field: value })	Find documents matching the field value
db.collection.find({ age: { $gt: 25 } })	Find documents where age is greater than 25
db.collection.findOne({ field: value })	Find a single document matching the query
cursor.toArray()	Convert the cursor to an array of documents

Key Takeaways

Use db.collection.find(query) to search documents with optional filters.

find() returns a cursor; use toArray() or iterate to access documents.

Use findOne() to get a single document instead of a cursor.

Always check query syntax and operators to avoid empty results.

An empty query object {} returns all documents in the collection.