Question: Show the names of people who have been on the negative side of debates at least twice.
Schema: create table debate_people (negative varchar, PRIMARY KEY (negative)); create table people (name varchar, people_id varchar, PRIMARY KEY (name))
SQL: select t2.name from debate_people as t1 join people as t2 on t1.negative = t2.people_id group by t2.name having count(*) >= 2