| stu_no | stu_name | sub_no | sub_name | score |
| 1 | 张三 | 001 | 语文 | 90 |
| 1 | 张三 | 002 | 数学 | 60 |
| 2 | 李四 | 001 | 语文 | 89 |
| 2 | 李四 | 002 | 数学 | 86 |
select distinct stu_name from student_score where stu_name not in (select distinct stu_name from student_score where score <= 80)
select stu_name from student_score group by stu_name having min(score) > 80
select distinct stu_name from student_score where score > 80
select stu_name from student_score group by sub_name having min(score) > 80
