Show me the countries of the perpetrators.
select country from perpetrator;
What are the names of perpetrators whose country is "China"?
select t1.name from people as t1 join perpetrator as t2 on t1.people_id = t2.people_id where t2.country = "China";
How about those whose country is not "China"?
select t1.name from people as t1 join perpetrator as t2 on t1.people_id = t2.people_id where t2.country != "China";