SQL> start e61i.sql
SQL> -- Q1 (i)
SQL> 
SQL> TTITLE "Enrolments from before 2005 with NULL Mark"
SQL> 
SQL> SELECT StudentId, CourseCode
  2  FROM Enrolment
  3  WHERE Year < 2005
  4    AND Mark IS NULL
  5  /

Thu Sep 01                                                           page    1
                  Enrolments from before 2005 with NULL Mark

 STUDENTID COURSECO                                                           
---------- --------                                                           
   2010052 COMP1100                                                           

SQL> start e61ii.sql
SQL> -- Q1 (ii) COMP6240
SQL> 
SQL> TTITLE "Courses which All Students have Taken"
SQL> 
SQL> SELECT CourseCode
  2  FROM Course
  3  WHERE NOT EXISTS
  4   ( SELECT StudentId FROM Student
  5  	WHERE StudentId NOT IN
  6  	 ( SELECT StudentId FROM Enrolment
  7  	   WHERE Enrolment.CourseCode = Course.CourseCode ) )
  8  /

no rows selected

SQL> start e61iii.sql
SQL> -- Q1 (iii)
SQL> 
SQL> TTITLE "Minimum and Maximum Marks attained by Each Student"
SQL> 
SQL> SELECT StudentId, MIN(Mark), MAX(Mark)
  2  FROM Enrolment
  3  GROUP BY StudentId
  4  /

Thu Sep 01                                                           page    1
              Minimum and Maximum Marks attained by Each Student

 STUDENTID  MIN(MARK)  MAX(MARK)                                              
---------- ---------- ----------                                              
   2010001         67         81                                              
   2010018         79         79                                              
   2010035         55         66                                              
   2010052         44         53                                              
   2010069         70         78                                              

SQL> start e61iv.sql
SQL> -- Q1 (iv)
SQL> 
SQL> TTITLE "Students Enrolled in Courses Given by Depts Other Than COMP"
SQL> 
SQL> SELECT StudentId FROM Enrolment
  2  WHERE CourseCode NOT IN
  3    ( SELECT CourseCode FROM Course
  4  	 WHERE Dept = 'COMP' )
  5  /

Thu Sep 01                                                           page    1
         Students Enrolled in Courses Given by Depts Other Than COMP

 STUDENTID                                                                    
----------                                                                    
   2010001                                                                    
   2010035                                                                    
   2010035                                                                    
   2010035                                                                    
   2010018                                                                    
   2010052                                                                    
   2010052                                                                    

7 rows selected.

SQL> start e61v.sql
SQL> -- Q1 (v)
SQL> 
SQL> TTITLE "Classmates of Student 2020001"
SQL> 
SQL> SELECT DISTINCT B.StudentId
  2  FROM Enrolment A, Enrolment B
  3  WHERE B.CourseCode = A.CourseCode
  4    AND B.Year = A.Year
  5    AND B.Sem = A.Sem
  6    AND B.StudentId != A.StudentId
  7    AND A.StudentId = 2010001
  8  /

Thu Sep 01                                                           page    1
                        Classmates of Student 2020001

 STUDENTID                                                                    
----------                                                                    
   2010035                                                                    
   2010052                                                                    

SQL> exit