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 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 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 the relation account (customer, balance) where customer is a primary key and there are no null values. We would like to rank customers according to decreasing balance. The customer with the largest balance gets rank 1. Ties are not broke but ranks are skipped: if exactly two customers have the largest balance they each get rank 1 and rank 2 is not assigned.

Query1:
  Select A.customer, count(B.customer)
  From account A, account B
  Where A.balance <=B.balance
  Group by A.customer

Query2:
  Select A.customer, 1+count(B.customer)
  From account A, account B
  Where A.balance < B.balance
  Group by A.customer

Consider these statements about Query1 and Query2.

1. Query1 will produce the same row set as Query2 for some but not all databases.

2. Both Query1 and Query2 are correct implementation of the specification

3. Query1 is a correct implementation of the specification but Query2 is not

4. Neither Query1 nor Query2 is a correct implementation of the specification

5. Assigning rank with a pure relational query takes less time than scanning in decreasing balance order assigning ranks using ODBC.

Which two of the above statements are correct?