计算学生总分，并将该总分插入另一个表中，并将该学生的ID一起输入

I'm developing a simple student information system, for now i have 300 students and six subjects, so when i want to add marks obtained by each student i use html form and php script to add those marks, for each student i add marks for six subjects that is one subject at a time, so i'm asking if there is the way where by php can allow me retrieve one student and add all the marks for the six subjects at once and then take another and so on. Also i want to calculate total marks for each student and store those total in another table with respective student id so that i can know who is the first student and who is the last by using that total marks of each student.I'm developing a simple student information sys