[MSSQL] 파일 그룹별로 디스크 할당량, 사용량, 할당 가능량 조회 쿼리

SELECT  a.[NAME] as '파일 그룹명'
        , b.size*8 /1024 as 'PhysicalSize (MB)'
        ,(b.Size - sum(total_pages))*8/1024 as 'UnAllocationSize (MB) '
        , sum(total_pages) * 8 /1024 as 'TotalAllocation (MB)'
        , sum(used_pages)*8 /1024 as 'UsedAllocation (MB)'
        , sum(data_pages) *8/1024 as 'DataSize (MB)'
        , sum(total_pages-used_pages)*8/1024 as 'FreeSize (MB)'
  FROM SYS.filegroups a with (nolock)
 INNER JOIN ( SELECT data_space_id, sum(size) as 'size'
                FROM Sys.database_files with(nolock)
               GROUP BY data_space_id 
             ) b 
    ON a.data_space_id = b.data_space_id
 INNER JOIN SYS.allocation_units c with(nolock)
    ON a.data_space_id = c.data_space_id
 GROUP BY a.name, b.Size
 ORDER BY 1, 2