这种只能手动创建好表后，导出ddl语句

参考修改下

 CREATE TABLE BB   AS  SELECT TO_CHAR(ROWNUM) AS 序号,
               TO_CHAR(NAME) AS 列名,
               TO_CHAR(TYPE$) AS 列数据类型,
               TO_CHAR(LENGTH$) AS 列定义长度 ,
               TO_CHAR(NULLABLE$) AS 是否允许为空 ,
               TO_CHAR(DEFVAL) AS 缺省值
          FROM SYSCOLUMNS  WHERE 1=2 

DECLARE
    OBJECTNAME VARCHAR ;
    OBJECT_ID  NUMBER;
BEGIN
    FOR AA IN (SELECT OWNER,
            OBJECT_NAME,
            OBJECT_ID
       FROM ALL_OBJECTS
      WHERE OBJECT_TYPE='TABLE'
        AND OWNER ='SYSDBA'
        AND OBJECT_TYPE NOT IN ('##PLAN_TABLE',
                                '##HISTOGRAMS_TABLE') LIMIT 3 )
    LOOP
     INSERT INTO  BB (   SELECT '表名' AS 序号,
               AA.OWNER||AA.OBJECT_NAME AS 列名,
               '' AS 列数据类型,
               '' AS 列定义长度,
               '' AS 是否允许为空,
               '' AS 缺省值
          FROM DUAL
        UNION ALL
        SELECT TO_CHAR(ROWNUM) AS 序号,
               TO_CHAR(NAME) AS 列名,
               TO_CHAR(TYPE$) AS 列数据类型,
               TO_CHAR(LENGTH$) AS 列定义长度 ,
               TO_CHAR(NULLABLE$) AS 是否允许为空 ,
               TO_CHAR(DEFVAL) AS 缺省值
          FROM SYSCOLUMNS
         WHERE ID = AA.OBJECT_ID) ;
    COMMIT ;
    END LOOP;
END;


SELECT * FROM BB;