Applying Oracle Pivot to get horizentle data - oracle

Question

(I am new to Oracle pivot.)
The result of my code is as follow.
ROWNUM C0 M SS
------- --- ---------- ---------- ----------
1 a a__ 3.5
2 a abd 1.5
3 a abe 3.5
4 a ace 5.5
5 b a__ 35
6 b abd 15
7 b abe 35
8 b ace 55
Items in C0 shows vertically as expected.
Now,The purpose is to show the values in C0 horizently.
How to modify my code to make result as follow?
ROWNUM M a b
---------- --------- ---------- ----------
1 a__ 3.5 35
2 abd 1.5 15
3 abe 3.5 35
4 ace 5.5 55
My code is as below;
CREATE TABLE T4 (
C0 VARCHAR2(10),
C1 VARCHAR2(10),
C2 NUMBER
);
INSERT INTO T4 VALUES ('a','abd',1);
INSERT INTO T4 VALUES ('a','abd',2);
INSERT INTO T4 VALUES ('a','abe',3);
INSERT INTO T4 VALUES ('a','abe',4);
INSERT INTO T4 VALUES ('a','ace',5);
INSERT INTO T4 VALUES ('a','ace',6);
INSERT INTO T4 VALUES ('b','abd',10);
INSERT INTO T4 VALUES ('b','abd',20);
INSERT INTO T4 VALUES ('b','abe',30);
INSERT INTO T4 VALUES ('b','abe',40);
INSERT INTO T4 VALUES ('b','ace',50);
INSERT INTO T4 VALUES ('b','ace',60);
SELECT ROWNUM,rr.C0,rr.M, rr.ss
FROM
(
SELECT C0,C1 M, AVG(C2) ss FROM T4 GROUP BY C0, C1
UNION
SELECT C0,SUBSTR(C1,1,1)||'__' ,AVG(C2) ss FROM T4 GROUP BY C0,SUBSTR(C1,1,1) ) rr
ORDER BY rr.C0,rr.M ASC;

Answer 1

You can achieve the result in two ways.
Using PIVOT and using a traditional technique (CASE WHEN).
PIVOT is the recommended technique to use. But I have written both just for your reference.
-- Using PIVOT --
WITH DATAA AS (
SELECT ROWNUM,rr.C0,rr.M, rr.ss
FROM
(
SELECT C0,C1 M, AVG(C2) ss FROM T4 GROUP BY C0, C1
UNION
SELECT C0,SUBSTR(C1,1,1)||'__' ,AVG(C2) ss FROM T4 GROUP BY C0,SUBSTR(C1,1,1) ) rr
)
-- USING PIVOT
SELECT
ROWNUM,
TAB.*
FROM
(
SELECT
*
FROM
(
SELECT
M,
C0,
SS
FROM
DATAA
) PIVOT (
SUM ( SS )
FOR ( C0 )
IN ( 'a' AS A, 'b' AS B )
)
ORDER BY
1
) TAB;
-- Using Traditional technique --
WITH DATAA AS (
SELECT ROWNUM,rr.C0,rr.M, rr.ss
FROM
(
SELECT C0,C1 M, AVG(C2) ss FROM T4 GROUP BY C0, C1
UNION
SELECT C0,SUBSTR(C1,1,1)||'__' ,AVG(C2) ss FROM T4 GROUP BY C0,SUBSTR(C1,1,1) ) rr
)
-- TRADITIONAL WAY
SELECT
ROWNUM,
M,
A,
B
FROM
(
SELECT
M,
MAX(CASE
WHEN C0 = 'a' THEN SS
END) AS A,
MAX(CASE
WHEN C0 = 'b' THEN SS
END) AS B
FROM
DATAA
GROUP BY
M
ORDER BY
M
);
-- Output --
db<>fiddle demo
Cheers!!