MySQL行转列

 数据库设计类似于这种结构

要求通过SQL查询出如下结构的数据：

 其SQL语句如下

SELECT username, 
MAX(CASE course WHEN 'chinese' THEN score ELSE 0 END) AS '语文',
MAX(CASE course WHEN 'math' THEN score ELSE 0 END) AS '数学',
MAX(CASE course WHEN 'english' THEN score ELSE 0 END) AS '英语'
FROM score
GROUP BY username