---Creating new table----

CREATE TABLE UNPIVOT_TRAINING (
  ID              NUMBER,
  CUSTOMER_ID     NUMBER,
  PROUCT_CODE_AB  NUMBER,
  PROUCT_CODE_AC  NUMBER,
  PROUCT_CODE_AD  NUMBER,
  PROUCT_CODE_AE  NUMBER
);

---INSERTING DATA---
INSERT INTO UNPIVOT_TRAINING VALUES (1, 101, 10, 20, 30, NULL);
INSERT INTO UNPIVOT_TRAINING VALUES (2, 102, 40, NULL, 50, NULL);
INSERT INTO UNPIVOT_TRAINING VALUES (3, 103, 60, 70, 80, 90);
INSERT INTO UNPIVOT_TRAINING VALUES (4, 104, 100, NULL, NULL, NULL);
COMMIT;

---CHECKING_DATA---

SELECT * FROM UNPIVOT_TRAINING;

---convert columns to rows in sql----

SELECT *
FROM   UNPIVOT_TRAINING
UNPIVOT (QUANTITY FOR PRODUCT_CODE IN (PROUCT_CODE_AB AS 'AB',PROUCT_CODE_AC AS 'AC',PROUCT_CODE_AD AS 'AD',PROUCT_CODE_AE AS 'AE'));