Show the ids for all the faculty members
select facid from faculty
For each of them, also count the number of students advised.
select t1.facid, count(*) from faculty as t1 join student as t2 on t1.facid = t2.advisor group by t1.facid
Who have at least 2 students?
select t1.facid from faculty as t1 join student as t2 on t1.facid = t2.advisor group by t1.facid having count(*) >= 2