SQL & PL/SQL

SQL> select ename from emp where job='CLERK';

ENAME
----------
Smith
Adams
James
Miller

SQL> select ename from emp where job='SALESMAN';

ENAME
----------
Allen
Ward
Martin
Turner

SQL> select ename from emp where job='MANAGER'
2 /

ENAME
----------
Jones
Blake
Clark


I need a SQL query to get data in this format .

CLERK SALESMAN MANAGER
----- -------- ---------
Smith Allen Jones
Adams Ward Blake
James Martin Clark

thanks!