-- Returns Reserved space, Used space and Free space per datafile in a database
SELECT 
	filegroup_name(groupid) as Filegroup,
	[name], 
	filename, 
	[size]/128.0 as TotalSizeInMB,
	FILEPROPERTY([name], 'SpaceUsed')/128.0 as SpaceUsedInMB,
	([size] - FILEPROPERTY([name], 'SpaceUsed'))/128.0 as FreeSpaceInMB
FROM sysfiles