How Data base size and path

SELECTdb.[database_id] AS 'DB ID',
db
.[name] AS 'Database Name',
af
.[name] AS 'Logical Name',
af
.[filename] AS 'Physical Location',
(((
CAST(af.[size] AS DECIMAL(18,4)) * 8192) /1024) /1024) AS 'File Size (MB)',

((((
CAST(af.[size] AS DECIMAL(18,4)) * 8192) /1024) /1024) /1024) AS 'File Size (GB)'
FROM sys.databases db INNER JOIN sys.sysaltfiles af ON db.database_id = af.dbid

WHERE [fileid] in (1,2)

===================================================
SELECT name,Size, physical_name AS current_file_location

FROM sys.master_files=============================
sp_helpdb