What are the distinct first names of students?
select distinct fname from student
Of those, which have a gradepoint of at least 3.8 in one course?
select distinct t3.fname from enrolled_in as t1 join gradeconversion as t2 join student as t3 on t1.grade = t2.lettergrade and t1.stuid = t3.stuid where t2.gradepoint >= 3.8