จนถึงตอนนี้ฉันมีเครดิตหรือไม่ ถ้ามีกี่เครดิต ?ไม่จำเป็นต้องใช้ตารางทั้งหมด
Do I have any credits so far , if yes how many ?It is not neccessary to use all the tables.
 student_record:  student_id [ int]  course_id [ int]  semester [ int]  grade [ varchar]  how [ varchar]  transfer_source [ varchar]  earn_credit [ varchar]  repeat_term [ varchar]  test_id [ varchar] 
SELECT DISTINCT total_credit FROM student WHERE student_id = 1