SELECT SUM(bytes) / (1024 * 1024*1024) AS free_space, tablespace_name

FROM dba_free_space

GROUP BY tablespace_name;

SELECT a.tablespace_name,

a.bytes/1024/1024/1024 total,

b.bytes/1024/1024/1024 used,

c.bytes/1024/1024/1024 free,

(b.bytes * 100) / a.bytes "% USED ",

(c.bytes * 100) / a.bytes "% FREE "

FROM sys.sm$ts_avail a, sys.sm$ts_used b, sys.sm$ts_free c

WHERE a.tablespace_name = b.tablespace_name

AND a.tablespace_name = c.tablespace_name;