T-SQL - Convert binary data to/from Base64 (or other string representation)

Is there a Microsoft T-SQL statement that will allow y开发者_StackOverflow中文版ou to convert a binary data type (like image) to/from a string representation like Base64.

its easy enough in .net (Convert.ToBase64 & Convert.FromBase64) but is this possible using SQL alone, something like (obviously pseudocode)

SELECT CastAsBase64(binary_field) As Base64BinaryField
FROM   SomeTable
WHERE  ID = @ID

Could not see this in the linked answers;

;with test(blob) as (select 0x776962626C65)

select blob from test
  for xml raw, binary base64

>>  <row blob="d2liYmxl"/>

I had an old bookmark to this site that converts it using an xml conversion not really straightforward but it works.: http://blogs.msdn.com/b/sqltips/archive/2008/06/30/converting-from-base64-to-varbinary-and-vice-versa.aspx