SQL & PL/SQL

Hai All

I have created a table with four columns and i need to change the column position

For example Table name is emp

columns are name,address,empno,salary

And now i need to change the columns position while i am displaying select * from emp not as select col1,col3,col2..

Pls tell if it possible

And while adding f it possible to add a new column into a specific column position

For example

In the above table shall we add a new column in a second position

pls give some good examples

Thanks in advance

Srikkanth.M