oracle查看空闲可用表空间sql语句

      有时候我们经常要查看可用的表空间还有多少，通常我们市看dba_free_space 这张表，但这张表看起来不怎么直观，所以就写了下面的sql语句，比较直观的查看可用表空间容量：

     

select tablespace_name,
 max_blocks,
 count_blocks,
 sum_free_blocks,
 sum_free_MB,
 sum_space_MB,
 round(100*sum_free_blocks/sum_alloc_blocks,2)||'%' pct_free
from
 (select tablespace_name,
  sum(blocks) sum_alloc_blocks,
  sum(bytes)/1024/1024 sum_space_MB
 from dba_data_files
 group by tablespace_name
 ),
 (select tablespace_name free_space_tablespace_name,
  max(blocks) max_blocks,
  count(blocks) count_blocks,
  sum(blocks) sum_free_blocks,
  sum(BYTES)/1024/1024 sum_free_MB
 from dba_free_space
 group by tablespace_name
 )
where tablespace_name = free_space_tablespace_name