/*1.比较表结构 */ 

(select column_name 

          from user_tab_columns 

         where table_name = 'T_A' 

        minus 

        select column_name 

          from user_tab_columns 

         where table_name = 'T_B') 

union  

(select column_name 

         from user_tab_columns 

        where table_name = 'T_B' 

       minus 

       select column_name 

         from user_tab_columns 

        where table_name = 'T_A');