可用空间表空间

SELECT SUBSTR(TABLESPACE_NAME, 1, 40) TABLESPACE,
       CASE
         WHEN USED_PERCENT >= 95 THEN
          'CRITICO'
         WHEN USED_PERCENT >= 75 THEN
          'ATENÇÃO'
         ELSE
          'NORMAL'
       END ALERTA,
       -- % USED        
       ROUND(USED_PERCENT, 2) USED_PERCENT,
       TABLESPACE_SIZE TABLESPACE_BLOCKS,
       --USED_SPACE
       ROUND((USED_SPACE * 8192) / (1024 * 1024), 2) USED_MB,
       ROUND(((USED_SPACE * 8192) / (1024 * 1024) / 1024), 2) USED_GB,
       --TABLESPACE_SIZE
       ROUND((TABLESPACE_SIZE * 8192) / (1024 * 1024), 2) TABLESPACE_EXT_MB,
       ROUND(((TABLESPACE_SIZE * 8192) / (1024 * 1024) / 1024), 2) TABLESPACE_EXT_GB,
       ROUND((((TABLESPACE_SIZE * 8192) / (1024 * 1024) / 1024) -
             ((USED_SPACE * 8192) / (1024 * 1024) / 1024)),
             2) RESTANTE_GB
  FROM DBA_TABLESPACE_USAGE_METRICS X
 ORDER BY USED_PERCENT DESC;