SELECT UPPER(F.TABLESPACE_NAME) TABLESPACE_NAME, --  表空间名,
                               D.TOT_GROOTTE_MB TOT_GROOTTE_MB, --   表空间大小(G),
                               D.TOT_GROOTTE_MB - F.TOTAL_BYTES USEDMB, ---已使用空间(G),
                               TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) / D.TOT_GROOTTE_MB * 100,
                                             2),
                                       '990.99') || '%' USAGERATIO, -- 使用比,
                               F.TOTAL_BYTES, -- 空闲空间(G),
                               d.MAXBYTES --表空间最大能扩到多大
                             
                          FROM (SELECT TABLESPACE_NAME,
                                       ROUND(SUM(BYTES) / (1024 * 1024* 1024), 3) TOTAL_BYTES
                                  FROM SYS.DBA_FREE_SPACE
                                 GROUP BY TABLESPACE_NAME) F,
                               (SELECT DD.TABLESPACE_NAME,
                                       ROUND(SUM(DD.BYTES) / (1024 * 1024* 1024), 3) TOT_GROOTTE_MB,
                                       ROUND(sum(dd.MAXBYTES)/(1024 * 1024* 1024), 3) MAXBYTES
                                  FROM SYS.DBA_DATA_FILES DD
                                 GROUP BY DD.TABLESPACE_NAME) D
                         WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME
                         ORDER BY 2 DESC

查询表空间所有相关信息sql：select * from dba_data_files;

dba_data_files视图字段说明