How to identify the Total/Available/Used Physical Memory in database server using script ?

SELECT (total_physical_memory_kb/1024.)/1024. 'Total Physical Memory(GB)', 

	   (available_physical_memory_kb/1024.)/1024. 'Available Physical Memory(GB)',

	    (100 / ((total_physical_memory_kb/1024.)/1024.)) * (((total_physical_memory_kb/1024.)/1024.) - ((available_physical_memory_kb/1024.)/1024.)) 'Used Physical Memory(%)' ,

	   (100 / ((total_physical_memory_kb/1024.)/1024.)) * ((available_physical_memory_kb/1024.)/1024.)  'Available Physical Memory(%)',

	   system_memory_state_desc 'Memory Status'

FROM sys.dm_os_sys_memory