Determine available disk size with a sql query

I need to determine the available space on the drive where my database lives. I know about the xp_fixeddrives procedure but how do I get the info for the开发者_如何学C specific drive where my database resides?

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Something like this?

declare @DatabaseName sysname 
set @DatabaseName = 'master'

declare @Drive table(DriveName char, FreeSpaceInMegabytes int)
insert @Drive execute xp_fixeddrives

select 
    mas.type_desc FileType, 
    mas.name FileName, 
    mas.physical_name PhysicalFileName, 
    mas.size * 8 / 1024 FileSizeInMegabytes,
    drv.DriveName, 
    drv.FreeSpaceInMegabytes
from sys.master_files mas
    left join @Drive drv on
        left(mas.physical_name, 1) = drv.DriveName
where database_id = db_id(@DatabaseName)

Set @DatabaseName accordingly.

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    SELECT Drive
    ,   TotalSpaceGB
    ,   FreeSpaceGB
    ,   PctFree
    ,   PctFreeExact
    FROM
    (SELECT DISTINCT
        SUBSTRING(dovs.volume_mount_point, 1, 10) AS Drive
    ,   CONVERT(INT, dovs.total_bytes / 1024.0 / 1024.0 / 1024.0) AS TotalSpaceGB
    ,   CONVERT(INT, dovs.available_bytes / 1048576.0) / 1024 AS FreeSpaceGB
    ,   CAST(ROUND(( CONVERT(FLOAT, dovs.available_bytes / 1048576.0) / CONVERT(FLOAT, dovs.total_bytes / 1024.0 /
                         1024.0) * 100 ), 2) AS NVARCHAR(50)) + '%' AS PctFree
    ,   CONVERT(FLOAT, dovs.available_bytes / 1048576.0) / CONVERT(FLOAT, dovs.total_bytes / 1024.0 / 1024.0) * 100 AS PctFreeExact                
    FROM    sys.master_files AS mf
    CROSS APPLY sys.dm_os_volume_stats(mf.database_id, mf.file_id) AS dovs) AS DE

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You haven't mentioned your version of SQL Server. Starting with SQL Server 2005 you can get plenty of information from sys.database_files and relate that to the output of xp_fixeddrives.