Instance name is null - SQL Server I recently checked this in my SQL server instances:

SQL Server 2012 EE:

-- get current SQL Server name\instance name
  SELECT @@SERVERNAME
-- get current machine name and instance name
  SELECT SERVERPROPERTY('MachineName'), SERVERPROPERTY ('InstanceName')


And the results show NULL value for instance name for some of the instances.

I did go through Instance name NULL

Sample output for one of my servers for SELECT SERVERPROPERTY('MachineName'), SERVERPROPERTY ('InstanceName')

was

'Class024.dev.com', Null

Should I change the Instance name? Is it necessary or does it returns NULL if the instance is the default one?
It does return 'Null' if you've only got a default instance. I tried it in SQL 2005 and SQL 2008R2.
Otherwise, @@SERVERNAME should be the same as ServerProperty('MachineName') + '\' + ServerProperty('InstanceName')
Tested this also in SQL 2005 and SQL 2008R2.