มีนักเรียนกี่คน?ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
How many students are there?It is not neccessary to use all the tables.
 student:  stuid [ number]  lname [ text]  fname [ text]  age [ number]  sex [ text]  major [ number]  advisor [ number]  city_code [ text] 
SELECT COUNT(*) FROM student