Find

In MongoDB, we use the find and findOne methods to retrieve data from a collection, similar to how the SELECT statement is used in MySQL databases.

Find One

To select data from a collection in MongoDB, we can use the findOne() method, which returns the first occurrence in the selection.

Example

To find the first document in the "customers" collection, use the following code:

// Setup MongoDB connection
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  var dbo = db.db("mydb");
  dbo.collection("customers").findOne({}, function(err, result) {
    if (err) throw err;
    console.log(result.name);
    db.close();
  });
});

Output

Company Inc.

Find All

To select all documents from a collection, use the find() method. It returns all occurrences in the selection.

Example

To find all documents in the "customers" collection, use the following code:

// Same setup as previous example

dbo.collection("customers").find({}).toArray(function(err, result) {
  if (err) throw err;
  console.log(result);
  db.close();
});

Output

[
  { _id: ..., name: 'John', address: 'Highway 71'},
  // Additional documents...
]

Find Some

You can specify a projection object as the second parameter of the find() method to include or exclude certain fields in the result.

Example

To return only the "name" and "address" fields of all documents in the "customers" collection:

// Same setup as previous example

dbo.collection("customers").find({}, { projection: { _id: 0, name: 1, address: 1 } }).toArray(function(err, result) {
  if (err) throw err;
  console.log(result);
  db.close();
});

Output

[
  { name: 'John', address: 'Highway 71'},
  // Additional documents...
]

Warning

You cannot specify both 0 and 1 values in the same object, except for the _id field. If you specify a field with the value 0, all other fields get the value 1, and vice versa.