oracle中如何查看一个表所占空间的大小, 这张表包含blob字段

写了一个，你试试：
select a.TABLESPACE_NAME "TableSpace Name",
round(a.BYTES / 1024 / 1024) "MB Allocated",
round((a.BYTES-nvl(b.BYTES, 0)) / 1024 / 1024) "MB Used",
nvl(round(b.BYTES / 1024 / 1024), 0) "MB Free",
round(((a.BYTES-nvl(b.BYTES, 0))/a.BYTES)*100,2) "Pct Used"
from (select TABLESPACE_NAME,
sum(BYTES) BYTES
from sys.dba_data_files
group by TABLESPACE_NAME) a,
(select TABLESPACE_NAME,
sum(BYTES) BYTES
from sys.dba_free_space
group by TABLESPACE_NAME) b
where a.TABLESPACE_NAME = b.TABLESPACE_NAME (+)
And a.tablespace_name in ('表空间名','表空间名','表空间名');

加上blob的大小在dba_lobs查找对应关系，再加上index大小。