Show names of all high school students who do not have any friends.
create table highschooler (name varchar, id varchar, PRIMARY KEY (name)); create table highschooler (name varchar, PRIMARY KEY (name)); create table friend (student_id varchar, PRIMARY KEY (student_id))
select name from highschooler except select t2.name from friend as t1 join highschooler as t2 on t1.student_id = t2.id