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 Email, Username INTO [csv://Clients.txt] FROM [Clients] WHERE Email = 'support@mycompany.com'

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 Email, Username INTO [csv://Clients.txt;delimiter=tab] FROM [Clients] WHERE Email = 'support@mycompany.com'

C#

String connectionString = "OAuthClientId=MyClientId;OAuthClientSecret=MyClientSecret;CallbackURL=http://localhost:33333";

using (FreshBooksConnection connection = new FreshBooksConnection(connectionString)) {
  FreshBooksCommand cmd = new FreshBooksCommand("SELECT Email, Username INTO [csv://Clients.txt] FROM [Clients] WHERE Email = 'support@mycompany.com' ", connection);
  int rowsAffected = cmd.ExecuteNonQuery();
} 

VB.NET

Dim connectionString As [String] = "OAuthClientId=MyClientId;OAuthClientSecret=MyClientSecret;CallbackURL=http://localhost:33333" 

Using connection As New FreshBooksConnection(connectionString)
  Dim cmd As New FreshBooksCommand("SELECT Email, Username INTO [csv://Clients.txt] FROM [Clients] WHERE Email = 'support@mycompany.com'", 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 = "OAuthClientId=MyClientId;OAuthClientSecret=MyClientSecret;CallbackURL=http://localhost:33333";

using (FreshBooksConnection connection = new FreshBooksConnection(connectionString)) {
  FreshBooksCommand cmd = new FreshBooksCommand("SELECT * INTO [Clients] IN [csv://filename=c:/Clients.csv;delimiter=tab] FROM [Clients] WHERE Email = 'support@mycompany.com'", connection);
  int rowsAffected = cmd.ExecuteNonQuery();
} 

VB.NET

Dim connectionString As [String] = "OAuthClientId=MyClientId;OAuthClientSecret=MyClientSecret;CallbackURL=http://localhost:33333" 

Using connection As New FreshBooksConnection(connectionString)
  Dim cmd As New FreshBooksCommand("SELECT * INTO [Clients] IN [csv://filename=c:/Clients.csv;delimiter=tab] FROM [Clients] WHERE Email = 'support@mycompany.com'", connection)
  Dim rowsAffected As Integer = cmd.ExecuteNonQuery()
End Using