What are the names of students who have more than one advisor?
SELECT T1.name FROM student AS T1 JOIN advisor AS T2 ON T1.id  =  T2.s_id GROUP BY T2.s_id HAVING count(*)  >  1
students who have more than one advisor refers to a JOIN between student and advisor tables on student ID and counting the number of advisors each student has, where the count is greater than 1;