Rows to Columns and Columns to Rows

-- Create a table and insert data into the table.
gaussdb=# CREATE TABLE test_p1(id INT, math INT, english INT);
gaussdb=# INSERT INTO test_p1 VALUES (1,84,78), (2,98,82), (3,68,59);
gaussdb=# SELECT * FROM test_p1;
 id | math | english 
----+------+---------
  3 |   68 |      59
  1 |   84 |      78
  2 |   98 |      82
(3 rows)

-- Convert rows to columns.
gaussdb=# SELECT * FROM test_p1 UNPIVOT(score FOR class IN(math, english));
 id |  class  | score 
----+---------+-------
  3 | MATH    |    68
  3 | ENGLISH |    59
  1 | MATH    |    84
  1 | ENGLISH |    78
  2 | MATH    |    98
  2 | ENGLISH |    82
(6 rows)

-- Delete.
gaussdb=# DROP TABLE test_p1;

-- Create a table and insert data into the table.
gaussdb=# CREATE TABLE test_p2(id INT, class VARCHAR(20), score INT);
gaussdb=# INSERT INTO test_p2 VALUES (1,'math',64), (1,'english',78);
gaussdb=# INSERT INTO test_p2 VALUES (2,'math',98), (2,'english',82);
gaussdb=# INSERT INTO test_p2 VALUES (3,'math',68), (3,'english',59);
gaussdb=# SELECT * FROM test_p2;
 id |  class  | score 
----+---------+-------
  3 | math    |    68
  3 | english |    59
  1 | math    |    64
  1 | english |    78
  2 | math    |    98
  2 | english |    82
(6 rows)

-- Convert columns to rows.
gaussdb=# SELECT * FROM test_p2 PIVOT(MAX(score) FOR class IN('math','english'));
 id | 'math' | 'english' 
----+--------+-----------
  3 |     68 |        59
  1 |     64 |        78
  2 |     98 |        82
(3 rows)

-- Delete.
gaussdb=# DROP TABLE test_p2;