SQL 퀘스트

> 정답

38. SELECT COUNT(*) AS department_cnt
    FROM departments;
39. SELECT e.name,
    d.name
    FROM employees e INNER JOIN departments d ON e.department_id = d.id;
40. SELECT e.name
    FROM employees e INNER JOIN departments d ON e.department_id = d.id
    WHERE d.name = '기술팀';
41. SELECT d.name,
    COUNT(e.id) AS employee_cnt
    FROM departments d LEFT JOIN employees e ON d.id = e.department_id
    GROUP BY d.id;
42. SELECT d.name
    FROM departments d LEFT JOIN employees e ON d.id = e.department_id
    WHERE e.id IS NULL;
43. SELECT e.name
    FROM employees e INNER JOIN departments d ON e.department_id = d.id
    WHERE d.name = '마케팅팀';