CREATE TABLE assignedto (scientist NUMBER, project CLOB)
CREATE TABLE projects (code CLOB, name CLOB, hours NUMBER)
CREATE TABLE scientists (ssn NUMBER, name CLOB)

What are the names of projects that have not been assigned?
SELECT name FROM projects WHERE NOT code IN (SELECT project FROM assignedto)
SELECT "name" FROM "projects" WHERE NOT "code" IN (SELECT "project" FROM "assignedto")