select f.tablespace_name,sum(f.bytes_free + f.bytes_used)/1024/1024/1024 "total 
GB",sum((f.bytes_free + f.bytes_used) - nvl(p.bytes_used, 0))/1024/1024/1024 "Free 
GB",sum(nvl(p.bytes_used, 0))/1024/1024/1024 "Used GB" 
from 
v_$temp_space_header f, dba_temp_files d, v_$temp_extent_pool p 
where f.tablespace_name(+) = d.tablespace_name and f.file_id(+) = d.file_id and 

p.file_id(+) = d.file_id 
group by f.tablespace_name;