oracle查看表空间大小及使用情况

SELECT a.tablespace_name "表空间名",
       total "表空间大小",
       free "表空间剩余大小",
       (total - free) "表空间使用大小",
       total / (1024 * 1024 * 1024) "表空间大小(G)",
       free / (1024 * 1024 * 1024) "表空间剩余大小(G)",
       (total - free) / (1024 * 1024 * 1024) "表空间使用大小(G)",
       round((total - free) / total, 4) * 100 "使用率 %"
  FROM (SELECT tablespace_name, SUM(bytes) free
          FROM dba_free_space
         GROUP BY tablespace_name) a,
       (SELECT tablespace_name, SUM(bytes) total
          FROM dba_data_files
         GROUP BY tablespace_name) b 
 WHERE a.tablespace_name = b.tablespace_name;

备注：用户需要有dba权限，否则会报表找不到的错误。
 
参考：http://blog.itpub.net/31477110/viewspace-2152749/
          https://www.cnblogs.com/lipera/p/6201434.html