GATE CSE 2023 | Question: 51

Question

Consider the following table named $\text{Student}$ in a relational database. The primary key of this table is $\text{rollNum}.$

$\text{Student}$
$\begin{array}{|c|l|c|c|}
\hline \underline{\text{rollNum}} & \text{name} & \text{gender} & \text{marks} \\
\hline \hline 1 & \text{Naman} & \mathrm{M} & 62 \\
\hline 2 & \text{Aliya} & \mathrm{F} & 70 \\
\hline 3 & \text{Aliya} & \mathrm{F} & 80 \\
\hline 4 & \text{James} & \mathrm{M} & 82 \\
\hline 5 & \text{Swati} & \mathrm{F} & 65 \\
\hline
\end{array}$

The $\text{SQL}$ query below is executed on this database.

SELECT *
FROM Student
WHERE gender = 'F' AND
    marks  > 65;

The number of rows returned by the query is ___________.

Comments

$\color{\red}{\text{DBMS:}}$

Question 1: Degree(Arity) of a Relation

Question 2: SQL question Number of Tuples

Question 3: Primary Index on Data File, Binary Search

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By the way, that is not age as per the question in the examination. That is actually the marks obtained by the students. Using Age here makes the question unintentionally funny.

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@Vishal_kumar98 Haha, Corrected. 

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The correct answer is 2

Answer 1

The output of the given SQL query is simply to return the female students whose marks is $>65$. we can also solve by first we retrieve all the female students then we can select marks $>65$.

ROll	Name	Marks	Gender
$1$	Aliya	70	Female
$2$	Aliya	80	Female
$5$	Swati	65	Female

output is as follows:

Roll	Name	Marks	Gender
$1$	Aliya	70	Female
$2$	Aliya	80	Female

So the output of the given query is $2$.

Answer 2

The output of the given SQL query is simply to return the female students whose marks is $>65$. we can also solve by first we retrieve all the female students then we can select marks $>65$.

ROll	Name	Marks	Gender
$2$	Aliya	70	Female
$3$	Aliya	80	Female
$5$	Swati	65	Female

output is as follows:

Roll	Name	Marks	Gender
$2$	Aliya	70	Female
$3$	Aliya	80	Female

So the output of the given query is $2$.