SQL Online Quiz

Q 1 - Consider the following schema −

STUDENTS(student_code, first_name, last_name, email, 
         phone_no, date_of_birth, honours_subject, percentage_of_marks);

Which of the following query would display names of all the students whose honours subject is English, or honours subject is Spanish and percentage of marks more than 80?

A - select first_name, last name from students where (honours_subject = “English” or honours_subject = “Spanish” ) and percentage_of_marks > 80;

B - select first_name, last name from students where honours_subject = “English” or honours_subject = “Spanish” and percentage_of_marks > 80;

C - select first_name, last name from students where honours_subject = “English” and honours_subject = “Spanish” or percentage_of_marks > 80;

D - select first_name, last name from students where (honours_subject = “English”) and honours_subject = “Spanish” and percentage_of_marks > 80;

Q 2 - Consider the following schema −

STUDENTS(student_code, first_name, last_name, email, 
         phone_no, date_of_birth, honours_subject, percentage_of_marks);

Which of the following query would display names and percentage of marks of all students sorted by honours subject, and then order by percentage of marks?

A - select first_name, last name, honours_subject, percentage_of_marks from students order by honours_subject, percentage_of_marks;

B - select first_name, last name, honours_subject, percentage_of_marks order by percentage_of_marks desc from students;

C - select first_name, last name, percentage_of_marks from students order by percentage_of_marks desc;

D - select first_name, last name, percentage_of_marks from students order by percentage_of_marks, honours_subject;

Q 3 - For some particular assignment, you need to compare two values, if both are equal, the result would be null, and if the values are not equal then the first value should be returned. Which function should you use?

A - NVL

B - NVL2

C - NULLIF

D - COALESCE

Q 4 - Which of the following is true about a group function?

A - Group functions operate on sets of rows to produce multiple results per group.

B - DISTINCT keyword makes a group function consider duplicate values.

C - Group functions ignore null values.

D - None of the above.

Q 5 - Which of the following is not true about single-row subqueries?

A - Single row subqueries return one row from the inner SELECT statement.

B - Single row subqueries return one row from the outer SELECT statement.

C - Single row subqueries use single-row comparison operators.

D - All of the above.

Q 6 - Which of the following is not true about inserting news rows to a table?

A - The INSERT INTO statement is used for inserting new rows to a table

B - You cannot insert rows with NULL values to a table.

C - You may insert a new row containing values for each column.

D - All of the above.

Q 7 - Which statement allows conditional update, or insertion of data into a table simultaneously?

A - INSERT statement

B - MERGE statement

C - UPDATE statement

D - None of the above

Q 8 - Which of the following is true about deleting a table from the database?

A - All the data in the table are deleted

B - The table structure is removed

C - The indexes in the table are deleted

D - All of the above.

Q 9 - Which of the following code will create an index named

stu_marks_ind on the columns student_code and percentage_of_marks of the STUDENTS table.

Now which will delete the index stu_marks_ind.

Which of the following code will delete an index stu_marks_ind on the columns student_code and percentage_of_marks of the STUDENTS table?

A - drop index stu_marks_ind;

B - delete index stu_marks_ind;

C - drop stu_marks_ind;

D - drop index stu_marks_ind on students;

Q 10 - A database administrator can

A - Create users.

B - Create privileges.

C - Grant privileges.

D - All of the above.