oracle 查看表空间实际占用情况

SELECT tablespace_name 表空间名,
               round(SUM(bytes) / 1000 / 1000 / 1000, 2) alloc_bytes,
               round(SUM(maxbytes) / 1000 / 1000 / 1000, 2) maxbytes
          FROM dba_data_files
         GROUP BY tablespace_name;
SELECT tablespace_name 表空间名,
               round(SUM(nvl(bytes, 1)) / 1000 / 1000 / 1000, 2) free_space 
          FROM DBA_FREE_SPACE
         GROUP BY tablespace_name;
		 
		 
SELECT tablespace_name 表空间名,
               round(SUM(bytes) / 1000 / 1000 / 1000, 2) 占用,
               round(SUM(maxbytes) / 1000 / 1000 / 1000, 2) 最大
          FROM dba_data_files
         GROUP BY tablespace_name;
		 
SELECT tablespace_name 表空间名,
               round(SUM(nvl(bytes, 1)) / 1000 / 1000 / 1000, 2) 空闲 
          FROM DBA_FREE_SPACE
         GROUP BY tablespace_name;
		 		 
SELECT a.tablespace_name, 
round(a.bytes/1024/1024/1024,2) 总空间, 
round(b.bytes/1024/1024/1024,2) 使用空间, 
round(c.bytes/1024/1024/1024,2) 空闲空间, 
(b.bytes * 100) / a.bytes "% USED ", 
(c.bytes * 100) / a.bytes "% FREE " 
FROM sys.sm$ts_avail a, sys.sm$ts_used b, sys.sm$ts_free c 
WHERE a.tablespace_name = b.tablespace_name 
AND a.tablespace_name = c.tablespace_name(+); 
		 
SELECT a.tablespace_name 表空间名, 
round(a.bytes/1024/1024/1024,2) 总空间, 
round(b.bytes/1024/1024/1024,2) 使用空间, 
round(c.bytes/1024/1024/1024,2) 空闲空间, 
d.maxbytes 最大空间,
(b.bytes * 100) / a.bytes "% USED ", 
(c.bytes * 100) / a.bytes "% FREE " 
FROM sys.sm$ts_avail a, sys.sm$ts_used b, sys.sm$ts_free c,
(SELECT tablespace_name,round(SUM(maxbytes) / 1024 / 1024 / 1024, 2) maxbytes FROM dba_data_files GROUP BY tablespace_name) d
WHERE a.tablespace_name = b.tablespace_name 
AND a.tablespace_name = c.tablespace_name(+)
AND a.tablespace_name = d.tablespace_name; 


select a.tablespace_name,total,free,total-free used from 
　（select tablespace_name,sum(bytes)/1024/1024/1024 total from dba_data_files
   　　group by tablespace_name) a, 
　　( select tablespace_name,sum(bytes)/1024/1024/1024 free from dba_free_space
   　　group by tablespace_name) b
　　where a.tablespace_name=b.tablespace_name;