Converting rows into column using pivot function

we can convert row into columns using pivot function
let us consider the following data as sample data

DEPTNO	ENAME	JOB
10	ALLEN	ANALYST
10	JONES	CLERK
10	FORD	MANAGER
10	ABCD	PRESIDENT
10	CLARK	SALESMAN
20	MILLER	ANALYST
20	SMITH	CLERK
20	WARD	MANAGER
20	efgh	PRESIDENT
20	MARTIN	SALESMAN
30	SCOTT	ANALYST
30	TURNER	CLERK
30	ADAMS	MANAGER
30	BLAKE	PRESIDENT
30	KING	SALESMAN

now create a table as emp_jobs with this data


using pivot function
we are converting rows into columns

select * from emp_jobs pivot( min(ename) for job in ('PRESIDENT','MANAGER','CLERK','ANALYST','SALESMAN'));

the output is in the form

DEPTNO	PRESIDENT'	MANAGER'	CLERK'	ANALYST'	SALESMAN'
20	efgh	WARD	SMITH	MILLER	MARTIN
10	ABCD	FORD	JONES	ALLEN	CLARK
30	BLAKE	ADAMS	TURNER	SCOTT	KING

but while using pivot function aggregate function should be used 

we can also achieve this conversion without using pivot function using this sql query

 select
   a1.deptno,
   a1.ename  AS PRESIDENT,
   a2.ename AS MANAGER,
   a3.ename AS CLERK
from
   emp_jobs  a1,
   emp_jobs a2,
   emp_jobs  a3
   where
   a1.deptno=a2.deptno
   and a2.deptno=a3.deptno
   and a3.deptno=a1.deptno
   and a1.job = 'PRESIDENT'
   and a2.job = 'MANAGER'
   and a3.job ='CLERK';