CALCULAR TAMANHOS PARA TABLE SPACE

SELECT df.tablespace_name "Tablespace"
       ,totalusedspace "Used MB"
       ,(df.totalspace - tu.totalusedspace) "Free MB"
       ,df.totalspace "Total MB"
       ,round(100 * ((df.totalspace - tu.totalusedspace) / df.totalspace)) "Pct. Free"
       ,SYSDATE dateds
  FROM (SELECT tablespace_name
              ,round(SUM(bytes) / 1048576) TotalSpace
          FROM dba_data_files
         GROUP BY tablespace_name) df
      ,(SELECT round(SUM(bytes) / (1024 * 1024)) totalusedspace
              ,tablespace_name
          FROM dba_segments
         GROUP BY tablespace_name) tu
 WHERE df.tablespace_name = tu.tablespace_name
   AND tu.tablespace_name = NVL(NULL, tu.tablespace_name) --TROCAR NULL PELO NOME DA TABLE_SPACE