注意存在表空间不存在于dba_free_space 中（可能是因为表空间过大已爆掉）

--1、查看表空间的名称及大小
SELECT t.tablespace_name, round(SUM(bytes / (1024 1024)), 0) ts_size
FROM dba_tablespaces t, dba_data_files d
WHERE t.tablespace_name = d.tablespace_name
GROUP BY t.tablespace_name;
--2、查看表空间物理文件的名称及大小
SELECT tablespace_name,
file_id,
file_name,
round(bytes / (1024 1024), 0) total_space
FROM dba_data_files
ORDER BY tablespace_name;
--3、查看回滚段名称及大小
SELECT segment_name,
tablespace_name,
r.status,
(initial_extent / 1024) initialextent,
(next_extent / 1024) nextextent,
max_extents,
v.curext curextent
FROM dba_rollback_segs r, v$rollstat v
WHERE r.segment_id = v.usn(+)
ORDER BY segment_name;
--4、查看控制文件
SELECT NAME FROM v$controlfile;
--5、查看日志文件
SELECT MEMBER FROM v$logfile;
--6、查看表空间的使用情况
SELECT SUM(bytes) / (1024 1024) AS free_space, tablespace_name
FROM dba_free_space
GROUP BY tablespace_name;
SELECT a.tablespace_name,
a.bytes total,
b.bytes used,
c.bytes free,
(b.bytes 100) / a.bytes "% USED ",
(c.bytes 100) / a.bytes "% FREE "
FROM sys.sm$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;
--7、查看数据库库对象
SELECT owner, object_type, status, COUNT() count#
FROM all_objects
GROUP BY owner, object_type, status;
--8、查看数据库的版本　
SELECT version
FROM product_component_version
WHERE substr(product, 1, 6) = 'Oracle';
--9、查看数据库的创建日期和归档方式
SELECT created, log_mode, log_mode FROM v$database;

--1G=1024MB
--1M=1024KB
--1K=1024Bytes
--1M=11048576Bytes
--1G=102411048576Bytes=11313741824Bytes
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

数据库会存在temp表空间

查询temp表空间和使用情况时需要单独的脚本

select d.tablespace_name,
space "sum_space(m)",
blocks sum_blocks,
used_space "used_space(m)",
round(nvl(used_space, 0) / space 100, 2) "used_rate(%)",
nvl(free_space, 0) "free_space(m)"
from (select tablespace_name,
round(sum(bytes) / (1024 1024), 2) space,
sum(blocks) blocks
from dba_temp_files
group by tablespace_name) d,
(select tablespace_name,
round(sum(bytes_used) / (1024 1024), 2) used_space,
round(sum(bytes_free) / (1024 1024), 2) free_space
from v$temp_space_header
group by tablespace_name) f
where d.tablespace_name = f.tablespace_name(+)

TABLESPACE_NAME sum_space(m) SUM_BLOCKS used_space(m) used_rate(%) free_space(m)

但这种情况并不能表示目前临时表空间的使用情况，比如某临时表空间已经使用了100%，该操作完毕后，临时表空间的HWM标志没有被回收，所以如果想知道当前的临时表空间使用，需要通过v$sort_usgae来确定：

select sum(blocks*8192)/1024/1024 from v$sort_usage;

临时表空间，请查询DBA_TEMP_FREE_SPACE

SELECT TABLESPACE_NAME, FREE_SPACE/1024/1024 AS "FREE SPACE(M)"
FROM DBA_TEMP_FREE_SPACE
WHERE TABLESPACE_NAME = '&tablespace_name';

临时表空间，请查询DBA_TEMP_FILES
SELECT TABLESPACE_NAME, FILE_ID, FILE_NAME, BYTES/1024/1024 AS "SPACE(M)"
FROM DBA_TEMP_FILES
WHERE TABLESPACE_NAME = '&tablespace_name';

为空间不足的表空间增加数据文件
ALTER TABLESPACE &tablespace_name ADD DATAFILE '&datafile_name' SIZE 2G;
注：如果要为临时表空间扩容，使用下面的语句
ALTER TABLESPACE &tablespace_name ADD TEMPFILE '&datafile_name' SIZE 2G;

也可以修改数据文件的大小