How to query the Windows domain name for SQL Server

Yes.  There will come a time when you need to confirm the domain name of your server. Today, for example, I was setting up a bunch of RDP connections, and the domain name was a required credential.  This particular customer has several domains, so I just wanted to check quickly, to be sure I was targeting the right one.  I have posted 3 ways below, beginning with the easiest... which is the one I prefer to use!  Take a look and let me know if you have another way to do the same.

-- 1. Easiest

SELECT DEFAULT_DOMAIN() DomainName

-- 2. Also easy, but calling an xp

EXEC master..xp_loginconfig 'Default Domain'

-- 3. Way overkill, but it works

DECLARE @Domain VARCHAR(100), @key VARCHAR(100)

SET @key = 'system\controlset001\services\tcpip\parameters\'

EXEC master..xp_regread

      @rootkey = 'HKEY_LOCAL_MACHINE',

      @key = @key,

      @value_name = 'Domain',

      @value = @Domain OUTPUT

      SELECT @Domain [DomainName]

Just a quick tip, but I know that some of you will find it helpful.