Question

Comprehension

Consider the following relations A, B and C:

A
Id	Name	Age
12	Arun	60
15	Shreya	24
99	Rohit	11

 

B
Id	Name	Age
15	Shreya	24
25	Hari	40
98	Rohit	20
99	Rohit	11

 

C
Id	Phone	Area
10	2200	02
99	2100	01

How many tuples does the result of the following SQL query contain?

SELECT A.Id

FROM A

WHERE A.Age > ALL (SELECT B.Age

                                       FROM B WHERE B.Name = ‘Arun’)

1. 4
2. 3
3. 0
4. 1

Answer 1

Correct Answer - Option 2 : 3

The correct answer is option 2.

The ALL keyword specifies that the search condition is TRUE if the comparison is TRUE for every value that the subquery returns. If the subquery returns no value, the condition is TRUE.

There is no Name='Arun' in the B table. So it returns no value then the condition become is TRUE for every row. So Finally it prints the ID of the A table.

Id

12

15

99

Hence the correct answer is 3.