ORA-20000

This small reports the tablespace name, alloc size, free space, used space, extend size, total size in all the tablespaces in Oracle database.

select a.tablespace_name ,
       round(a.bytes_alloc / 1024 / 1024, 2) m_alloc,
       round(nvl(b.bytes_free, 0) / 1024 / 1024, 2) m_free,
       round((a.bytes_alloc - nvl(b.bytes_free, 0)) / 1024 / 1024, 2) m_used,
       round((maxbytes - a.bytes_alloc)/1024/1024, 2) m_extend,
       round(maxbytes/1024/1024,2) Max
from  ( select  f.tablespace_name,
               sum(f.bytes) as bytes_alloc,
               sum(decode(f.autoextensible, 'YES',greatest(f.maxbytes, f.bytes),'NO', f.bytes)) as maxbytes
        from dba_data_files f
        group by tablespace_name
        union all
        select f.tablespace_name,
               sum(f.bytes) as bytes_alloc, 
               sum(decode(f.autoextensible, 'YES',greatest(f.maxbytes, f.bytes),'NO', f.bytes)) as maxbytes
	      from dba_temp_files f
	      group by tablespace_name         
        ) a,
      ( select  f.tablespace_name,
               sum(f.bytes)  bytes_free
        from dba_free_space f
        group by tablespace_name) b
where a.tablespace_name = b.tablespace_name (+);