轉載，感謝分享的人

以系統管理員身份登入資料庫：

select * from sys.dba_tablespaces;

--查詢表空間使用情況
SELECT UPPER(F.TABLESPACE_NAME) "表空間名",
       D.TOT_GROOTTE_MB "表空間大小(M)",
       D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空間(M)",
       TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) / D.TOT_GROOTTE_MB * 100,
                     2),
               '990.99') || '%' "使用比",
       F.TOTAL_BYTES "空閒空間(M)",
       F.MAX_BYTES "最大塊(M)"
  FROM (SELECT TABLESPACE_NAME,
               ROUND(SUM(BYTES) / (1024 * 1024), 2) TOTAL_BYTES,
               ROUND(MAX(BYTES) / (1024 * 1024), 2) MAX_BYTES
          FROM SYS.DBA_FREE_SPACE
         GROUP BY TABLESPACE_NAME) F,
       (SELECT DD.TABLESPACE_NAME,
               ROUND(SUM(DD.BYTES) / (1024 * 1024), 2) TOT_GROOTTE_MB
          FROM SYS.DBA_DATA_FILES DD
         GROUP BY DD.TABLESPACE_NAME) D
 WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME
 ORDER BY 1;
--查詢表空間的free space
select tablespace_name,
       count(*) as extends,
       round(sum(bytes) / 1024 / 1024, 2) as MB,
       sum(blocks) as blocks
  from dba_free_space
 group by tablespace_name;
--查詢表空間的總容量
select tablespace_name, sum(bytes) / 1024 / 1024 as MB
  from dba_data_files
 group by tablespace_name;
--查詢表空間使用率
select total.tablespace_name,
       round(total.MB, 2) as Total_MB,
       round(total.MB - free.MB, 2) as Used_MB,
       round((1 - free.MB / total.MB) * 100, 2) || '%' as Used_Pct
  from (select tablespace_name, sum(bytes) / 1024 / 1024 as MB
          from dba_free_space
         group by tablespace_name) free,
       (select tablespace_name, sum(bytes) / 1024 / 1024 as MB
          from dba_data_files
         group by tablespace_name) total
 where free.tablespace_name = total.tablespace_name;