#1
select distinct name
       from grades g, grades, students
       where g.cno='cs210'
       and   grades.cno='cs240'
       and   g.stno=grades.stno
       and   g.stno=students.stno;


#2
select distinct name
       from students
       where stno in ( select stno from grades where cno='cs210'
                       minus
                       select stno from grades where cno='cs110');


#3
select distinct g.stno as stno1, grades.stno as stno2
       from grades g, grades
       where g.empno=grades.empno
       and   g.stno<grades.stno;


#4
select distinct i1.name, i2.name, i3.name
       from instructors i1, instructors i2, instructors i3,
            grades g1, grades g2, grades g3
       where g1.cno=g2.cno and g2.cno=g3.cno
       and i1.empno=g1.empno and i2.empno=g2.empno
       and i3.empno=g3.empno and i1.empno<i2.empno
       and i2.empno<i3.empno;


#5
select cno
       from grades, advising
       where grades.stno=advising.stno
       and   grades.empno=advising.empno;


#6
select instructors.name
       from instructors i1, instructors i2, instructors, grades,
       advising
       where i1.roomno=i2.roomno
       and   i1.empno!=i2.empno
       and   i1.empno=grades.empno
       and   grades.stno=advising.stno
       and   i2.empno=advising.empno
       and   instructors.empno=advising.empno;


#7
select name from instructors where
       not exists (select * from grades g,students where state='NH'
           and students.stno=g.stno and
           not exists (select * from grades where
               instructors.empno=empno and g.cno=cno));


#8
select distinct students.name as sname, instructors.name as iname
       from students,advising,grades,instructors
       where students.stno=advising.stno
       and advising.empno=instructors.empno
       and not advising.empno=grades.empno
       and not advising.stno=grades.stno;