SYSCOLUMNCOMMENTS视图中是列备注信息，新建表的列没有定义备注就没有数据。根据表名查列信息，参考：
select t1.owner,t1.table_name,t2.column_name,t3.comments,t2.nullable,t2.data_length,t2.data_type
from DBA_TABLES t1
inner join DBA_TAB_COLUMNS t2 on t1.owner=t2.owner and t1.table_name=t2.table_name
left join DBA_COL_COMMENTS t3 on t1.owner=t3.owner and t1.table_name=t3.table_name and t2.column_name=t3.column_name
where t1.owner='模式名'
and t1.table_name='表名';