自己寫的關於oracle表空間的統計

權限要求：
1、resource, dba

 --查看所有表空間的使用情況
select a.tablespace_name 表空間,
       a.total_bytes || 'M' 總計,
       a.total_bytes - nvl(b.free_bytes, 0) || 'M' 已使用,
       round((a.total_bytes - nvl(b.free_bytes, 0)) / a.total_bytes, 4) * 100 || '%' 已使用百分比,
       nvl(b.free_bytes, 0) || 'M' 剩餘,
       round(nvl(b.free_bytes, 0) / a.total_bytes, 4) * 100 || '%' 剩餘百分比
  from (select df.tablespace_name, sum(df.bytes) / 1024 / 1024 Total_bytes
          from dba_data_files df
         group by df.tablespace_name) a,
       (select fs.tablespace_name, sum(fs.bytes) / 1024 / 1024 Free_bytes
          from dba_free_space fs
         group by fs.tablespace_name) b
 where a.tablespace_name = b.tablespace_name(+)
 order by a.total_bytes desc