1. 查看表空间大小：
SELECT tablespace_name, SUM(bytes)/1024/1024 total FROM DBA_FREE_SPACE GROUP BY tablespace_name ORDER BY 2 DESC;
SQL> SELECT tablespace_name, SUM(bytes)/1024/1024 || 'MB' total FROM DBA_FREE_SPACE GROUP BY tablespace_name ORDER BY 2 DESC;
注意下上面两条SQL的排序，显然第一条SQL是我们需要的结果，按照表空间大小降序排列。之所以第二条SQL的排序乱，是因为使用了|| 'MB'连接字符串，则这个字段就作为字符串类型检索，排序时就会按照字符的ASCII进行排序。
2. 查看表空间使用率：
SELECT tablespace_name, SUM(bytes)/1024/1024 total FROM DBA_FREE_SPACE GROUP BY tablespace_name ORDER BY 2 DESC;
SQL> SELECT tablespace_name, SUM(bytes)/1024/1024 || 'MB' total FROM DBA_FREE_SPACE GROUP BY tablespace_name ORDER BY 2 DESC;
注意下上面两条SQL的排序，显然第一条SQL是我们需要的结果，按照表空间大小降序排列。之所以第二条SQL的排序乱，是因为使用了|| 'MB'连接字符串，则这个字段就作为字符串类型检索，排序时就会按照字符的ASCII进行排序。
2. 查看表空间使用率：
SQL>BREAK ON REPORT
SQL>COMPUT SUM OF tbsp_size ON REPORT
SQL>compute SUM OF used ON REPORT
SQL>compute SUM OF free ON REPORT
SQL>COL tbspname FORMAT a20 HEADING 'Tablespace Name'
SQL>COL tbsp_size FORMAT 999,999 HEADING 'Size|(MB)'
SQL>COL used FO
R
MAT 999,999 HEADING 'Used|(MB)'
SQL>COL free FO
R
MAT 999,999 HEADING 'Free|(MB)'
SQL>COL pct_used FORMAT 999,999 HEADING '% Used'
SQL>SELECT df.tablespace_name tbspname,
sum(df.bytes)/1024/1024 tbsp_size,
nvl(sum(e.used_bytes)/1024/1024,0) used,
nvl(sum(f.free_bytes)/1024/1024,0) free,
nvl((sum(e.used_bytes)*100)/sum(df.bytes),0) pct_used
FROM DBA_DATA_FILES df,
(SELECT file_id, SUM(nvl(bytes, 0)) used_bytes
FROM dba_extents
GROUP BY file_id) e,
(SELECT MAX(bytes) free_bytes, file_id
FROM dba_free_space
GROUP BY file_id) f
WHERE e.file_id(+) = df.file_id
AND df.file_id = f.file_id(+)
GROUP BY df.tablespace_name
ORDER BY 5 DESC;
视图定义：
视图定义：
