oracle 查询表空间大小

--1. 查看所有表空间大小select tablespace_name,sum(bytes)/1024/1024 from dba_data_files group by tablespace_name;--2. 已经使用的表空间大小select tablespace_name,sum(bytes)/1024/1024 from dba_free_space group by tablespace_name;--3. 所以使用空间可以这样计算select a.tablespace_name,total,free,total-free used from ( select tablespace_name,sum(bytes)/1024/1024 total from dba_data_files   group by tablespace_name) a, ( select tablespace_name,sum(bytes)/1024/1024 free from dba_free_space   group by tablespace_name) bwhere a.tablespace_name=b.tablespace_name;--4. 下面这条语句查看所有segment的大小。Select Segment_Name,Sum(bytes)/1024/1024 From User_Extents Group By Segment_Name