SQL Server 获取数据库大小

实例代码：

SELECT 
    DB_NAME(database_id) AS DatabaseName,
    SUM(size) * 8 / 1024 AS TotalSizeMB
FROM 
    sys.master_files
WHERE 
    type = 0  AND DB_NAME(database_id)='BAI'-- 0 表示数据文件
GROUP BY 
    DB_NAME(database_id);