CREATE TABLE debate_people (Name VARCHAR2, People_id VARCHAR2, Affirmative VARCHAR2)
CREATE TABLE people (Name VARCHAR2, People_id VARCHAR2, Affirmative VARCHAR2)

List the names of people that have not been on the affirmative side of debates.
SELECT Name FROM people WHERE NOT People_id IN (SELECT Affirmative FROM debate_people)
SELECT "Name" FROM "people" WHERE NOT "People_id" IN (SELECT "Affirmative" FROM "debate_people")