这个东西很有意思，先try drop table然后，在建表，然后循环插纪录

declare
       num number(12) :=0;
      
begin
       begin
            execute immediate
                    'drop table tb1';
       exception
            when
                 others
            then
                 null;
   end;
   execute immediate
      'create table tb1(
            aa number,
            bb number)';
  for num in select * from tb1 loop
     insert into tb1(aa,bb) values(num,num);
  end loop  ;
  commit;
end;