The following query returns the list of available fixed server roles
Members belonging to the sysadmin server role have the permissions to perform any activity in the server.
In order to find out if the logged in user is a sysadmin:
SELECT IS_SRVROLEMEMBER( 'sysadmin', '
Returns 1 if user is a sysadmin, 0 if user is not.
In order to find out the permissions associated with the sysadmin fixed server role:
EXEC sp_srvrolepermission 'sysadmin';