Simple scott/tiger query in horizontal format

Question

Hi Guys, this is my first thread to this forum, as I m a java developer and does not come across sql frequently.
I have a simple requirement.
I ll need this example to let u know, what is all I need.
You must be very well aware of the famous scott/tiger schema in Oracle database where the emp table has a many-one relationship with dept table.
Is there any way, where I can get the data in the below format (assuming one dept will have maximum 4 employees and minimum 0 employees)
DeptNo Employee1 Employee2 Employee3 Employee4
Accounting CLARK KING MILLER Null
Research JONES SCOTT ADAMS FORD
Sales ALLEN WARD NULL NULL
thanks in advance,
Abzee

Answer 1

Hi, Abzee,
Welcome to the forum!
That's called a Pivot and here's one way to do it:
WITH     got_rnum     AS
     SELECT     deptno
     ,     ename
     ,     ROW_NUMBER () OVER ( PARTITION BY  deptno
                         ORDER BY        ename
                       )     AS rnum
     FROM     scott.emp
SELECT       d.dname
,       MIN (CASE WHEN r.rnum = 1 THEN r.ename END)     AS employee1
,       MIN (CASE WHEN r.rnum = 2 THEN r.ename END)     AS employee2
,       MIN (CASE WHEN r.rnum = 3 THEN r.ename END)     AS employee3
,       MIN (CASE WHEN r.rnum = 4 THEN r.ename END)     AS employee4
FROM       scott.dept     d
JOIN       got_rnum     r     ON     r.deptno     = d.deptno
GROUP BY  d.dname
;To do a pivot, you must have columns or expressions that tell what row and column of the output correspond to each row of the input.
In this example, d.dname uniquely identifies the row of the output, but there's nothing that says that 'JONES' belongs in the employee1 column rather than the employee2 column. I used ROW_NUMBER to assign each employee a number, starting with 1 in each deptartment, for just that reason. I used ORDER BY ename, so that the employees will appear in alphabetic order. You could use any other way of sorting them (e.g., by salary or descending hiredate).
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