grade_sheet has the key (student_id, course_id). Each course's title and credits repeat once per student.

To make a table from a query, use CREATE TABLE … AS:

It copies the columns and the rows. It does not copy keys: add the primary key after it with ALTER TABLE … ADD PRIMARY KEY (…) (Chapter 5). CREATE TABLE and then INSERT … SELECT (Chapter 6) also work.

1. title and credits depend on which part of the key?
2. Create course_info(course_id, title, credits) with one row per course and course_id as its primary key.
3. Drop title and credits from grade_sheet, and make its course_id a foreign key to course_info.
4. Write the query that gives back the six rows of the old table: student_id, course_id, grade, title, credits.