Added comments and small changes

a.sql

@@ -1,4 +1,4 @@
--- What are the names (first name, last name) of all the students?
+--What are the names (first name, last name) of all the students? [72]
 
 select firstName, lastName
 from Students

b.sql

@@ -1,3 +1,5 @@
+--Same as in a) but produce a sorted listing. Sort first by last name and then by first name.
+
 select firstName, lastName
 from Students
 order by lastName, firstName

c.sql

@@ -1,3 +1,5 @@
+--Which students were born in 1975?
+
 select firstName, lastName
 from Students
 where pNbr like '1975%'

d.sql

@@ -1,3 +1,6 @@
+--What are the names of the female students, and which are their person numbers? 
+--The next-to-last digit in the person number is even for females[26]
+
 select firstName, pNbr
 from Students
 where substring(pNbr, LENGTH(pNbr) -1, 1) % 2 = 0

e.sql

@@ -1,2 +1,4 @@
-select distinct pNbr
+--How many students are registered in the database?
+
+select count(*)
 from Students

f.sql

@@ -1,3 +1,6 @@
+--Which courses are offered by the department of Mathematics
+--(course codes FMAxxx)? [24]
+
 select courseName
 from Courses
 where courseCode like '%FMA%'

g.sql

@@ -1,3 +1,5 @@
+--Which courses give more than five credits? [21]
+
 select courseName
 from Courses
 where credits > 5

h.sql

@@ -1,3 +1,6 @@
+--Which courses (course codes only) have been taken by the student with person 
+--num-ber 790101-1234? [7]
+
 select courseCode
 from TakenCourses
 where pNbr = '790101-1234'

i.sql

@@ -1,3 +1,5 @@
+--What are the names of these courses, and how many credits do they give?
+
 select courseName, credits, courseCode, pNbr
 from Courses
 join Students on Students.pNbr

j.sql

@@ -1,3 +1,5 @@
+--How many credits has the student taken?
+
 select sum(credits) as totalSum
 from Courses
 join Students on Students.pNbr

k.sql

@@ -1,3 +1,5 @@
+--Which is the student’s grade average on the courses that he has taken?
+
 select avg(TakenCourses.grade) as averageGrade, Students.pNbr
 from TakenCourses
 join Students on TakenCourses.pNbr = Students.pNbr

l.sql

@@ -1,3 +1,5 @@
+--Same questions as in questions h)-k), but for the student Eva Alm. [5]
+
 select firstName, lastName, avg(TakenCourses.grade) as averageGrade, TakenCourses.courseCode, Courses.courseName, sum(Courses.credits) as totalCredits
 from TakenCourses
 join Students on TakenCourses.pNbr = Students.pNbr

m.sql

@@ -1,4 +1,6 @@
-select distinct firstName
+--Which students have taken 0 credits? [16]
+
+select firstName, lastName
 from Students
 left join TakenCourses on Students.pNbr = TakenCourses.pNbr
 where TakenCourses.pNbr is null

n.sql

@@ -1,3 +1,6 @@
+--Which student has the highest grade average? Advice: define and use a view that
+--gives the person number and grade average for each student.
+
 DROP VIEW IF EXISTS StudentsAverages;
 
 CREATE VIEW StudentsAverages AS

o.sql

@@ -1,3 +1,6 @@
+--List the person number and total number of credits for all students.
+--Students with no credits should be included in the list! [72]
+
 DROP VIEW IF EXISTS StudentsCredits;
 
 CREATE VIEW StudentsCredits AS

p.sql

@@ -1,7 +1,9 @@
+--Same question as in question o) but with names instead of person numbers.
+
 DROP VIEW IF EXISTS StudentsCredits;
 
 CREATE VIEW StudentsCredits AS
-SELECT Students.firstName, sum(credits) as totalCredits
+SELECT Students.firstName, Students.lastName, sum(credits) as totalCredits
 FROM Students
 JOIN TakenCourses ON Students.pNbr = TakenCourses.pNbr
 JOIN Courses ON TakenCourses.courseCode = Courses.courseCode

q.sql

@@ -1,3 +1,5 @@
+--Is there more than one student with the same name? If so, who are these students? [7]
+
 SELECT firstName, lastName, count(*) as nbrOfStudents
 FROM Students
 GROUP BY firstName, lastName