数据量统计：

select sum(bytes)/1024/1024/1024 "total_size(G)" 
from dba_segments
where TABLESPACE_NAME not in ('SYSTEM','SYSAUX','USERS') 
and upper(TABLESPACE_NAME) not like '%TEMP%' 
and upper(TABLESPACE_NAME) not like '%UNDO%';

按数据文件大小统计：

select sum(bytes)/1024/1024/1024 as "DBFILE_SIZE" 
from dba_data_files
where TABLESPACE_NAME not in ('SYSTEM','SYSAUX','USERS') 
and upper(TABLESPACE_NAME) not like '%TEMP%' 
and upper(TABLESPACE_NAME) not like '%UNDO%';