PIVOT in Oracle Database

 CREATE TABLE pivot_test (

  id            NUMBER,

  customer_id   NUMBER,

  product_code  VARCHAR2(5),

  quantity      NUMBER

);

INSERT INTO pivot_test VALUES (1, 1, 'A', 10);

INSERT INTO pivot_test VALUES (2, 1, 'B', 20);

INSERT INTO pivot_test VALUES (3, 1, 'C', 30);

INSERT INTO pivot_test VALUES (4, 2, 'A', 40);

INSERT INTO pivot_test VALUES (5, 2, 'C', 50);

INSERT INTO pivot_test VALUES (6, 3, 'A', 60);

INSERT INTO pivot_test VALUES (7, 3, 'B', 70);

INSERT INTO pivot_test VALUES (8, 3, 'C', 80);

INSERT INTO pivot_test VALUES (9, 3, 'D', 90);

INSERT INTO pivot_test VALUES (10, 4, 'A', 100);

commit;

SELECT *

FROM   (SELECT product_code, quantity

        FROM   pivot_test)

PIVOT  (SUM(quantity) AS sum_quantity FOR (product_code) IN ('A' AS a, 'B' AS b, 'C' AS c));