最近项目中遇到，记录下来

方法可以是：

select '1' month from dual union all

select '2' month from dual union all

select '3' month from dual union all

select '4' month from dual union all

select '5' month from dual union all

select '6' month from dual union all

select '7' month from dual union all

select '8' month from dual union all

select '9' month from dual union all

select '10' month from dual union all

select '11' month from dual union all

select '12' month from dual;

或者

select lpad(level,2,0) from dual

connect by level<13