UNPIVOT clause

unpivot_clause:
    UNPIVOT [ { INCLUDE | EXCLUDE } NULLS ]
    ( { column | ( column [, column... ]) }
    pivot_for_clause
    unpivot_in_clause
    )

pivot_for_clause:
    FOR { column | ( column [, column... ]) }

unpivot_in_clause:
    IN
    ( { column | ( column [, column... ]) } [ AS { literal | ( literal [, literal... ]) } ]
        [, { column | ( column [, column... ]) } [ AS { literal | ( literal [, literal... ]) } ]]
    )

obclient> CREATE TABLE emp (
    empno NUMBER(4),
    job VARCHAR2(9),
    deptno NUMBER(2),
    sal NUMBER(7,2)
);

obclient> INSERT INTO emp VALUES
    (7369, 'CLERK', 20, 800),
    (7499, 'SALESMAN', 30, 1600),
    (7521, 'SALESMAN', 30, 1250),
    (7566, 'MANAGER', 20, 2975),
    (7654, 'SALESMAN', 30, 1250),
    (7698, 'MANAGER', 30, 2850),
    (7782, 'MANAGER', 10, 2450),
    (7788, 'ANALYST', 20, 3000),
    (7839, 'PRESIDENT', 10, 5000),
    (7844, 'SALESMAN', 30, 1500),
    (7876, 'CLERK', 20, 1100),
    (7900, 'CLERK', 30, 950),
    (7902, 'ANALYST', 20, 3000),
    (7934, 'CLERK', 10, 1300);

obclient> CREATE VIEW emp_pivot AS
    SELECT *
    FROM (SELECT job, deptno, sal FROM emp)
    PIVOT (
        SUM(sal)
        FOR deptno IN (10 AS dept_10, 20 AS dept_20, 30 AS dept_30, 40 AS dept_40)
    );

obclient> SELECT * FROM emp_pivot;

+-----------+---------+---------+---------+---------+
| JOB       | DEPT_10 | DEPT_20 | DEPT_30 | DEPT_40 |
+-----------+---------+---------+---------+---------+
| CLERK     |    1300 |    1900 |     950 |    NULL |
| SALESMAN  |    NULL |    NULL |    5600 |    NULL |
| MANAGER   |    2450 |    2975 |    2850 |    NULL |
| ANALYST   |    NULL |    6000 |    NULL |    NULL |
| PRESIDENT |    5000 |    NULL |    NULL |    NULL |
+-----------+---------+---------+---------+---------+
5 rows in set

obclient> SELECT *
    FROM emp_pivot
    UNPIVOT (
        sal
        FOR deptno IN (dept_10 AS 10, dept_20 AS 20, dept_30 AS 30, dept_40 AS 40)
    )
    ORDER BY deptno, job;

+-----------+--------+------+
| JOB       | DEPTNO | SAL  |
+-----------+--------+------+
| CLERK     |     10 | 1300 |
| MANAGER   |     10 | 2450 |
| PRESIDENT |     10 | 5000 |
| ANALYST   |     20 | 6000 |
| CLERK     |     20 | 1900 |
| MANAGER   |     20 | 2975 |
| CLERK     |     30 |  950 |
| MANAGER   |     30 | 2850 |
| SALESMAN  |     30 | 5600 |
+-----------+--------+------+
9 rows in set

obclient> SELECT *
    FROM (
        SELECT 1 AS id, 'Laptop' AS product, 100 AS q1, 150 AS q2 FROM dual
    )
    UNPIVOT (
        amount FOR quarter IN (q1, q2)
    );

+------+---------+--------+---------+
| ID   | PRODUCT | QUARTER | AMOUNT |
+------+---------+--------+---------+
|    1 | Laptop  | Q1      |    100 |
|    1 | Laptop  | Q2      |    150 |
+------+---------+--------+---------+
2 rows in set