How to copy the table in oracle?

•  Copy the table structure with data

        create table emp_copy as
          select *
            from Employee;

•   Copy the table structure with out data  

            CREATE TABLE Table2 AS 
               SELECT * FROM Table1 WHERE 1=0;
       Note: if condition is not validating then it wont copy the data. 

•  Copying selected columns from another table

                   CREATE TABLE newTable
                        AS (SELECT empno, ename
                                    FROM emp);