You can use the SELECT INTO statement to export formatted data to a file.

Data Export with an SQL Query

The following query exports data into a file formatted in comma-separated values (CSV):

SELECT City, CompanyName INTO [csv://[CData].[Sample].Customers.txt] FROM [[CData].[Sample].Customers] WHERE Country = 'US'

You can specify other formats in the file URI. The possible delimiters are tab, semicolon, and comma with the default being a comma. The following example exports tab-separated values:

SELECT City, CompanyName INTO [csv://[CData].[Sample].Customers.txt;delimiter=tab] FROM [[CData].[Sample].Customers] WHERE Country = 'US'

C#

String connectionString = "Server=127.0.0.1;Port=27017;Database=test;User=test;Password=test;";

using (MongoDBConnection connection = new MongoDBConnection(connectionString)) {
  MongoDBCommand cmd = new MongoDBCommand("SELECT City, CompanyName INTO [csv://[CData].[Sample].Customers.txt] FROM [[CData].[Sample].Customers] WHERE Country = 'US' ", connection);
  int rowsAffected = cmd.ExecuteNonQuery();
} 

VB.NET

Dim connectionString As [String] = "Server=127.0.0.1;Port=27017;Database=test;User=test;Password=test;" 

Using connection As New MongoDBConnection(connectionString)
  Dim cmd As New MongoDBCommand("SELECT City, CompanyName INTO [csv://[CData].[Sample].Customers.txt] FROM [[CData].[Sample].Customers] WHERE Country = 'US'", connection)
  Dim rowsAffected As Integer = cmd.ExecuteNonQuery()
End Using

You can specify other file formats in the URI. The following example exports tab-separated values:

C#

String connectionString = "Server=127.0.0.1;Port=27017;Database=test;User=test;Password=test;";

using (MongoDBConnection connection = new MongoDBConnection(connectionString)) {
  MongoDBCommand cmd = new MongoDBCommand("SELECT * INTO [[CData].[Sample].Customers] IN [csv://filename=c:/[CData].[Sample].Customers.csv;delimiter=tab] FROM [[CData].[Sample].Customers] WHERE Country = 'US'", connection);
  int rowsAffected = cmd.ExecuteNonQuery();
} 

VB.NET

Dim connectionString As [String] = "Server=127.0.0.1;Port=27017;Database=test;User=test;Password=test;" 

Using connection As New MongoDBConnection(connectionString)
  Dim cmd As New MongoDBCommand("SELECT * INTO [[CData].[Sample].Customers] IN [csv://filename=c:/[CData].[Sample].Customers.csv;delimiter=tab] FROM [[CData].[Sample].Customers] WHERE Country = 'US'", connection)
  Dim rowsAffected As Integer = cmd.ExecuteNonQuery()
End Using