图一：
| Nam | Course | Score |
| zhangsan | Chinese | 85 |
| zhangsan | Maths | 76 |
| zhangsan | English | 80 |
| lisi | Chinese | 82 |
| lisi | Maths | 90 |
| lisi | English | 55 |
图二：
| Nam | Chinese | Maths | English |
| zhangsan | 85 | 76 | 80 |
| lisi | 82 | 90 | 55 |
图一转图二：
SELECT Nam, SUM( IF (Course = ‘Chinese‘, Score, 0) ) Chinese, SUM(IF(Course = ‘Maths‘, Score, 0)) Maths, SUM( IF (Course = ‘English‘, Score, 0) ) english FROM t GROUP BY Nam
图二转图一：
(SELECT Nam, ‘Chinese‘Course, Chinese Score FROM t2) UNION (SELECT Nam, ‘Maths‘ Course , Maths Score FROM t2) UNION (SELECT Nam, ‘English‘ Course , English Score FROM t2) ORDER BY Nam DESC
原文：https://www.cnblogs.com/suheng01/p/9956633.html