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 FileId, ChildrenNum INTO [csv://Files.txt] FROM [Files] WHERE FileId = '119116'

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 FileId, ChildrenNum INTO [csv://Files.txt;delimiter=tab] FROM [Files] WHERE FileId = '119116'

C#

String connectionString = "Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;";

using (HDFSConnection connection = new HDFSConnection(connectionString)) {
  HDFSCommand cmd = new HDFSCommand("SELECT FileId, ChildrenNum INTO [csv://Files.txt] FROM [Files] WHERE FileId = '119116' ", connection);
  int rowsAffected = cmd.ExecuteNonQuery();
} 

VB.NET

Dim connectionString As [String] = "Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;" 

Using connection As New HDFSConnection(connectionString)
  Dim cmd As New HDFSCommand("SELECT FileId, ChildrenNum INTO [csv://Files.txt] FROM [Files] WHERE FileId = '119116'", 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 = "Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;";

using (HDFSConnection connection = new HDFSConnection(connectionString)) {
  HDFSCommand cmd = new HDFSCommand("SELECT * INTO [Files] IN [csv://filename=c:/Files.csv;delimiter=tab] FROM [Files] WHERE FileId = '119116'", connection);
  int rowsAffected = cmd.ExecuteNonQuery();
} 

VB.NET

Dim connectionString As [String] = "Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;" 

Using connection As New HDFSConnection(connectionString)
  Dim cmd As New HDFSCommand("SELECT * INTO [Files] IN [csv://filename=c:/Files.csv;delimiter=tab] FROM [Files] WHERE FileId = '119116'", connection)
  Dim rowsAffected As Integer = cmd.ExecuteNonQuery()
End Using