Free space in SQL server filegroups query

I just realised that in all my scripts that I use on a regular basis, I didn’t have one for working out free space in SQL Server filegroups. It’s not something that comes up too often but it’s handy to know. For methods of working out space in individual files, you could refer to this post on mssqltips.

-- Free space by filegroup
SELECT
FILEGROUP_NAME(data_space_id) as FilegroupName,
SUM(size/128.0) AS CurrentSizeMB, 
SUM(size/128.0 - CAST(FILEPROPERTY(name, 'SpaceUsed') AS INT)/128.0) AS FreeSpaceMB,
(
	SUM(size/128.0 - CAST(FILEPROPERTY(name, 'SpaceUsed') AS INT)/128.0) / -- FreeSpaceMB
	(SUM(size/128.0))  -- CurrentSizeMB
	* 100 -- Convert to percentage
) AS FilegroupPercentFree,
COUNT(*) as NumberOfFilesInFilegroup
FROM sys.database_files
WHERE data_space_id <> 0
GROUP BY FILEGROUP_NAME(data_space_id);

POST #100

I just realised as well that this is post #100 on my blog. I started it just to save some of my queries and ideas. Post #1 was a really simple query but it got me going.