Mysql：case when then end 的用法

drop table if exists t_score;
create table t_score
(
	id int primary key auto_increment,
	name varchar(20),
	course varchar(20),
	score double
) default charset = utf8;

insert into `t_score`(name,course,score) values
    (‘王海‘, ‘语文‘, 86),
    (‘王海‘, ‘数学‘, 83),
    (‘王海‘, ‘英语‘, 93),
    (‘陶俊‘, ‘语文‘, 88),
    (‘陶俊‘, ‘数学‘, 84),
    (‘陶俊‘, ‘英语‘, 94),
    (‘刘可‘, ‘语文‘, 80),
    (‘刘可‘, ‘数学‘, 86),
    (‘刘可‘, ‘英语‘, 88),
    (‘李春‘, ‘语文‘, 89),
    (‘李春‘, ‘数学‘, 80),
    (‘李春‘, ‘英语‘, 87);

SELECT name,
max(CASE course WHEN ‘语文‘ THEN score ELSE 0 END ) Chinese,
max(CASE course WHEN ‘数学‘ THEN score ELSE 0 END ) math,
max(CASE course WHEN ‘英语‘ THEN score ELSE 0 END ) English,
sum(score) score
FROM t_score  
GROUP BY name
union
select ‘TOTAL‘,
sum(CASE course WHEN ‘语文‘ THEN score ELSE 0 END ),
sum(CASE course WHEN ‘数学‘ THEN score ELSE 0 END ),
sum(CASE course WHEN ‘英语‘ THEN score ELSE 0 END ),
sum(score) from t_score;