แต่ละแผนกมีนักเรียนกี่คน?ไม่จำเป็นต้องใช้ตารางทั้งหมด
How many students are in each department?It is not neccessary to use all the tables.
 department:  dept_code [ text]  dept_name [ text]  school_code [ text]  emp_num [ number]  dept_address [ text]  dept_extension [ text] 
SELECT COUNT(*), dept_code FROM student GROUP BY dept_code