Find the last name of the individuals that have been contact individuals of an organization.
create table individuals (individual_last_name varchar, individual_id varchar, PRIMARY KEY (individual_last_name)); create table organization_contact_individuals (individual_id varchar, PRIMARY KEY (individual_id))
select distinct t1.individual_last_name from individuals as t1 join organization_contact_individuals as t2 on t1.individual_id = t2.individual_id