1. 查看所有表空間大小
select tablespace_name,sum(bytes)/1024/1024 from dba_data_files
group by tablespace_name;

2. 未使用的表空間大小
select tablespace_name,sum(bytes)/1024/1024 from dba_free_space
group by tablespace_name;

3. 所以使用空間可以這樣計算

統計表空間sql

set lines 180 pages 3000
select a.tablespace_name, total, free, total-free as used, substr(free/total * 100, 1, 5) as "FREE%", substr((total - free)/total * 100, 1, 5) as "USED%" from
(select tablespace_name, sum(bytes)/1024/1024/1024 as total from dba_data_files group by tablespace_name) a,
(select tablespace_name, sum(bytes)/1024/1024/1024 as free from dba_free_space group by tablespace_name) b
where a.tablespace_name = b.tablespace_name
order by a.tablespace_name

4.查詢表空間有哪幾個數據文件
select tablespace_name, file_id, file_name,
round(bytes/(1024*1024),0) total_space
from dba_data_files
where tablespace_name = 'DATA'
order by tablespace_name;

5. 還有在命令行情況下如何將結果放到一個文件里。
SQL> spool out.txt
SQL> select * from v$database;
SQL> spool off

增加表空間大小的四種方法
Meathod1：給表空間增加數據文件
ALTER TABLESPACE app_data ADD DATAFILE
'D:\ORACLE\PRODUCT\10.2.0\ORADATA\EDWTEST\APP03.DBF' SIZE 50M;

Meathod2：新增數據文件，并且允許數據文件自動增長
ALTER TABLESPACE app_data ADD DATAFILE
'D:\ORACLE\PRODUCT\10.2.0\ORADATA\EDWTEST\APP04.DBF' SIZE 50M
AUTOEXTEND ON NEXT 5M MAXSIZE 100M;

Meathod3：允許已存在的數據文件自動增長
ALTER DATABASE DATAFILE 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\EDWTEST\APP03.DBF'
AUTOEXTEND ON NEXT 5M MAXSIZE 100M;

Meathod4：手工改變已存在數據文件的大小
ALTER DATABASE DATAFILE 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\EDWTEST\APP02.DBF'
RESIZE 100M;