MySQL|外部キーを作成できません(エラー1072).

559 ワード

https://sql-factory.tistory.com/2164
https://heestory217.tistory.com/13
教授の数を学科名で印刷してください.

課題2-3の解答
select d.department_name, count(p.professor_id) 
from department d, professor p 
where d.department_id = p.department_id 
group by d.department_name;