SQL> select count(tablespace_name) from dba_data_files;

COUNT(TABLESPACE_NAME)
----------------------
                     5

col nbfiles new_value psz
select count(tablespace_name) nbfiles from dba_data_files;
set pagesize &psz

SQL> col nbfiles new_value psz
SQL> select count(tablespace_name) nbfiles from dba_data_files;

   NBFILES
----------
         5

SQL> set pagesize &psz
SQL>
SQL> SELECT
  2         TABLESPACE,
  3         DB_FILES,
  4         TB_SIZE,
  5         NVL(FREE_SPACE,0) TB_FREE,
  6         B.TB_SIZE - FREE.FREE_SPACE TB_USED,
  7         TOTAL.TOTAL_SPACE,
  8         (FREE_SPACE / TB_SIZE) * 100 "FREE%",
  9         ((B.TB_SIZE - FREE.FREE_SPACE) / TB_SIZE) * 100 "USED%",
 10         TO_CHAR(SYSDATE,'DD-MM-YYYY HH24:MI:SS') "Date"
 11  FROM
 12         (SELECT   TABLESPACE_NAME TABLESPACE
 13          FROM     DBA_DATA_FILES
 14          WHERE    TABLESPACE_NAME NOT LIKE 'TEMP%'
 15          GROUP BY TABLESPACE_NAME) A,
 16         (SELECT   TABLESPACE_NAME,
 17                   SUM(BYTES) / (1024 * 1024 * 1024) TB_SIZE
 18          FROM     DBA_DATA_FILES
 19          GROUP BY TABLESPACE_NAME) B,
 20         (SELECT   SUM(DECODE(AUTOEXTENSIBLE,'YES',MAXBYTES / (1024 * 1024 *
1024),
 21                                             BYTES / (1024 * 1024 * 1024)))
OTAL_SPACE,
 22                   TABLESPACE_NAME,
 23                   COUNT(* ) DB_FILES
 24          FROM     SYS.DBA_DATA_FILES
 25          GROUP BY TABLESPACE_NAME) TOTAL,
 26         (SELECT   TABLESPACE_NAME,
 27                   SUM(BYTES / (1024 * 1024 * 1024)) FREE_SPACE
 28          FROM     SYS.DBA_FREE_SPACE
 29          GROUP BY TABLESPACE_NAME) FREE
 30  WHERE  A.TABLESPACE = TOTAL.TABLESPACE_NAME
 31         AND TOTAL.TABLESPACE_NAME = FREE.TABLESPACE_NAME
 32         AND A.TABLESPACE = B.TABLESPACE_NAME
 33         AND FREE.TABLESPACE_NAME = A.TABLESPACE
 34         AND (FREE_SPACE / TOTAL_SPACE) * 100 <= 5;