Question: Show the names of editors that are on at least two journal committees.
Schema: create table editor (name varchar, editor_id varchar, PRIMARY KEY (name)); create table journal_committee (editor_id varchar, PRIMARY KEY (editor_id))
SQL: select t1.name from editor as t1 join journal_committee as t2 on t1.editor_id = t2.editor_id group by t1.name having count(*) >= 2