Question

Consider the following tables.

Student
Course
Student# Name
Course Name
Student#
1
Jay
DBMS
3
2
Alice
Automation
1
3
Jake
Electronics
4
4
May
How many tuples are present in the result of the query:
SELECT CourseName FROM Course
WHERE Student# = (
SELECT Student# FROM Student
WHERE Name = "Jack");
Select the correct Options:
A. 3
B. 0
C. 1
D. 4

Answer 1

B. 0

Step-by-step explanation:

Based on the given tables and query, let's break down the steps to determine the number of tuples present in the result:

1. First, we need to find the Student# for the student with the name "Jack" from the Student table:

SELECT Student# FROM Student WHERE Name = "Jack"

However, based on the given data, there is no student with the name "Jack." The available names are "Jay," "Alice," "Jake," and "May." Therefore, the subquery will not return any results.

2. Since the subquery did not return any results, there will be no value to compare with the Student# column in the Course table. As a result, the outer query will also not return any tuples.

Therefore, the result of the query will be an empty set, and the number of tuples in the result will be zero.