CREATE TABLE people (Name VARCHAR2, People_ID VARCHAR2)
CREATE TABLE debate_people (Negative VARCHAR2)

Show the names of people who have been on the negative side of debates at least twice.
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
SELECT "T2"."Name" FROM "debate_people" "T1" JOIN "people" "T2" ON "T1"."Negative" = "T2"."People_ID" GROUP BY "T2"."Name" HAVING COUNT(*) >= 2