Consider The Following Relational Scheme

Student (school-id, sch-roll-no, sname, saddress)
School (school-id, sch-name, sch-address, sch-phone)
Enrolment (school-id, sch-roll-no, erollno, examname)
ExamResult (Erollno, examname, marks)

What does the following SQL query output?

SELECT sch-name, COUNT (*) 
FROM School C, Enrolment E, 
ExamResult R 
WHERE E.school-id = C.school-id 
AND E.examname = R.examname 
AND E.erollno = R.erollno
AND R.marks = 100 AND S.school-id IN 
(SELECT school-id 
 FROM student 
 GROUP BY school-id 
 HAVING COUNT (*) > 200) 
GROUP BY school-id;

Consider The Following Relational Scheme

Student (school-id, sch-roll-no, sname, saddress)
School (school-id, sch-name, sch-address, sch-phone)
Enrolment (school-id, sch-roll-no, erollno, examname)
ExamResult (Erollno, examname, marks)

Consider the following tuple relational calculus query

{ t | ∃E ∈ Enrolment t = E.school-id ∧ 
| { x | x ∈ ExamResult B.school-id = 
t ∧ ( ∃B ∈ ExamResult B.erollno = 
x.erollno ∧ B.examname = x.examname ∧ 
B.marks > 35 } | ÷ | 
{ x | x ∈ Enrolment ∧ x.school-id = t } 
| * 100 > 35 }

If a student needs to score more than 35 marks to pass an exam what does the query return?

Consider the table employee(empId, name, department, salary) and the two queries Q₁, Q₂ below. Assuming that department 5 has more than one employee, and we want to find the employees who get higher salary than anyone in the department 5, which one of the statements is TRUE for any arbitrary employee table?

Q1:
Select e.empId 
From employee e 
Where not exists 
  (Select * From employee s
   where s.department = "5" and 
   s.salary >=e.salary);

Q2:
Select e.empId 
From employee e 
Where e.salary > Any 
( Select distinct salary 
From employee s 
Where s.department = "5");

Consider a database with three relation instances shown below. The primary keys for the Drivers and Cars relation are Did and cid respectively and the records are stored in ascending order of these primary keys as given in the tables. No indexing is available in the database.

D: Drivers Relation

Did	Dname	rating	Age
22	Karthikeyan	7	25
29	Salman	1	33
31	Boris	8	55
32	Amoldt	8	25
58	Schumacher	10	35
64	Sachin	7	35
71	Senna	10	16
74	Sachin	9	35
85	Rahul	3	25
95	Ralph	3	53

R: Reserves Relation

Did	cid	Day
22	101	10/10/06
22	102	10/10/06
22	103	8/10/06
22	104	7/10/06
31	102	10/11/06
31	103	6/11/06
31	104	12/11/06
64	101	5/9/06
64	102	8/9/06
74	103	8/9/06

C: Cars relation

cid	Cname	Color
101	Renault	Blue
102	Renault	Red
103	Ferrari	Green
104	Jaguar	Red

Select D.dname 
From Drivers D 
Where D.did in (SELECT R.did 
                From Cars C,Reserves R 
                WHERE R.cid = C.cid and C.color = 'green')

Let n be the number of comparisons performed when the above SQL query is optimally executed. If linear search is used to locate a tuple in a relation using primary key, then n lies in the range