第一步：建表
create table student_score
(
stuname varchar(10),
course varchar(20),
score decimal(5,1)
)
第二步:填充表
insert into student_score
select 'Steven','Operation System',88
union
select 'Steven','NetWork',79
union
select 'Nicole','Operation System',67
union
select 'Nicole','NetWork',53
第三步:sql实现
select stuname,
sum(case when course='NetWork' then score else 0 end) as NetWork,
sum(case when course='Operation System' then score else 0 end) as 'Operation System'
from student_score group by stuname
第四步:sql查询结果
stuname NetWork Operation System
---------- ---------------------------------------- ----------------------------------------
Nicole 53.0 67.0
Steven 79.0 88.0
（所影响的行数为 2 行）