只写了一半，剩下的写不来了，求指导

select score.课程号,课程名,学号,成绩
from score
left join course on course.课程号=score.课程号

望采纳哈，谢谢

select  a.课程号,a.课程名,c.学号,b.成绩
from course a
left join score b on b.课程号=a.课程号
left join student c on c.学号=b.学号

select co.课程号,co.课程名,sc.学号,sc.成绩
from course co
left join score sc
on co.课程号=sc.课程号
left join student st 
on sc.学号 = st.学号

select score.课程号,score.课程名,course.学号,course.成绩
from score score
full join course course   on course.课程号=score.课程号