Chapter 4, Problem 6PE

Explanation of Solution

Query

 create view student_grades (ID,GPA) as

     select ID, credit_points / decode (credit_sum, 0, NULL, credit_sum)

     from ((select ID, sum(decode(grade,NULL,0,credits)) as credit_sum,

         sum(decode(grade,NULL,0,credits*points)) as credit_sum

         from(takes natural join course) natural left outer join grade_points

  &...