--oracle查看该用户的所有表名字、表注释、字段名、字段注释、是否为空、字段类型

--oracle查看该用户的所有表名字、表注释、字段名、字段注释、是否为空、字段类型
select distinct TABLE_COLUMN.*,
                TABLE_NALLABLE.DATA_TYPE,
                TABLE_NALLABLE.NULLABLE
  from (select distinct utc.table_name  table_name,
                        utc.comments    table_comments,
                        ucc.column_name column_name,
                        ucc.comments    column_comments
          from user_tab_comments utc, user_col_comments ucc
         where utc.table_name = ucc.table_name
           ) TABLE_COLUMN,
       (select distinct table_name, column_name, nullable, DATA_TYPE
          from user_tab_cols
         ) TABLE_NALLABLE
 where TABLE_COLUMN.column_name = TABLE_NALLABLE.column_name
   and TABLE_COLUMN.TABLE_NAME = TABLE_NALLABLE.table_name