行转列，列转行-转

行转列 -- 用max 找出结果，case
SELECT user_name ,
MAX(CASE course WHEN '数学' THEN score ELSE 0 END ) 数学,
MAX(CASE course WHEN '语文' THEN score ELSE 0 END ) 语文,
MAX(CASE course WHEN '英语' THEN score ELSE 0 END ) 英语
FROM test_tb_grade
GROUP BY USER_NAME;

列转行--一列一列查出，然后将结果 union 成多列
select user_name, '语文' COURSE , CN_SCORE as SCORE from test_tb_grade2
union select user_name, '数学' COURSE, MATH_SCORE as SCORE from test_tb_grade2
union select user_name, '英语' COURSE, EN_SCORE as SCORE from test_tb_grade2
order by user_name,COURSE;

具体例子：http://www.jb51.net/article/109203.htm