跟行表差不多，可以参考一下下面的图和语句：
select owner,table_name, table_rowcount(owner,table_name) tab_rows,
table_used_space(owner,table_name)/1024.0/1024.0*page tab_mb
from dba_tables where owner='' and table_name like '%';

https://mp.weixin.qq.com/s/AgMBsXc9qkSiA5h2POP4pA

测试下下面这个SQL，看看是否合用。
注意最后条件里的表名参数值替换为你要查看数据量的表名

SELECT SCH.NAME AS SCHEMA_NAME
      ,TAB.ID
      ,TAB.NAME AS TABLE_NAME
      ,PAR.PARTITION_NAME
      ,CASE WHEN TAB.INFO3&0X3F IN (0x13, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27) THEN HTS.NAME || '(Huge TS)'
            ELSE TS.NAME
        END TABLESPACE_NAME
      ,TABLE_ROWCOUNT(SCH.NAME,TAB.NAME) AS "Table/Partition row count"
      ,ROUND(CAST(TABLE_USED_SPACE(SCH.NAME,TAB.NAME) AS NUMBER) * PAGE / 1024 / 1024,2) "Table/Partition used space(MB)"
      ,ROUND(CAST(TABLE_USED_PAGES(SCH.NAME,TAB.NAME) AS NUMBER) * PAGE / 1024 / 1024,2) "Table/Partition data size(MB)"
      ,IDXINFO.*
  FROM SYSOBJECTS TAB
  JOIN SYSOBJECTS IDX ON IDX.PID = TAB.ID
  JOIN SYSINDEXES IDXINFO ON IDXINFO.ID = IDX.ID AND BITAND(IDXINFO.XTYPE,0x01) = 0x00
  JOIN SYSOBJECTS SCH ON SCH.ID = TAB.SCHID 
  LEFT JOIN SYSHPARTTABLEINFO PAR ON PAR.PART_TABLE_ID = TAB.ID
  LEFT JOIN V$TABLESPACE TS ON TS.ID = IDXINFO.GROUPID 
  LEFT JOIN V$HUGE_TABLESPACE HTS ON HTS.ID = IDXINFO.GROUPID 
 WHERE SCH.NAME = USER
   AND NOT REGEXP_LIKE(TAB.NAME,'\$.*AUX$') --这个条件是用来过滤掉辅助表
   AND TAB.NAME LIKE '表名%'