select s.name, s.bl_prfs_id, p.name, p.prfs_id
from student s
left outer join professor p
on s.bl_prfs_id = p.prfs_id;
select * from student
left outer join professor
on student.major_id = professor.bl_major_id
union
select * from professor
left outer join student
on professor.bl_major_id = student.major_id
select s.name as 학생이름,
(select m.major_title from major m
where s.major_id = m.major_id) as 학과명
from student s
select s.name as 학생이름,
(select m.major_title
from major m
where s.major_id = m.major_id) as 학과명
from student s
select name as 학생이름
from student
where student.major_id = (select major.major_id from major where major_title = "컴퓨터공학과");
select name as 학생이름
from student
where student.major_id in (select major.major_id from major where major_title in ("국어국문학과", "컴퓨터공학과"));
