Question

Consider the relation Student (name, sex, marks), where the primary key is shown underlined, pertaining to students in a class that has at least one boy and girl. What does the following relational algebra expression produce? (Note: $\rho$ is rename operator)
$\prod name\left({\sigma }_{sex=female}\right(Student\left)\right)-{\prod }_{name}\left(Student\right)$
$\bowtie$${}_{(sex=female\wedge x=male\wedge marks\le m)}{\rho }_{n,x,m}\left(Student\right))$

• A. names of girl student with marks not less than some boy student
• B. names of girl students with more marks than all the boy students
• C. names of girl students with more marks than some boy student
• D. names of girl students with the highest marks

Answer 1

The correct option is B names of girl students with more marks than all the boy students

The given query computes the names of girl students with more marks than all the boy students.