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 - Which of the following is not true about Natural Joins?

A - Natural join is based on all columns in two tables having same name

B - It selects rows from the two tables having different values in the matched columns.

C - If columns having same names have different data types, it returns error.

D - None of the above.

Q 4 - Which of the following functions can be used on both numeric as well as non-numeric data?

A - COUNT

B - AVG

C - STDDEV

D - VARIANCE

Q 5 - You want to calculate the minimum percentage of marks obtained under each honours group students, where the minimum marks is more than the minimum marks in economics department. Under which clause should the subquery be?

A - WHERE clause

B - FROM clause

C - HAVING clause

D - None of the above.

Q 6 - In which of the following cases a DML statement is executed?

A - When new rows are added to a table.

B - When a table is created.

C - When a transaction is committed.

D - None of the above.

Q 7 - Consider the following schema −

LOCATIONS(subject_code, department_name, location_id, city);

Which code snippet will alter the table LOCATIONS and change the datatype of the column CITY to varchar2(30)?

A - ALTER TABLE locations MODIFY COLUMN (city varchar2(30));

B - MODIFY TABLE locations ADD (city varchar2(30));

C - ALTER TABLE locations MODIFY (city varchar2(30));

D - None of the above.

Q 8 - Which of the following is not true about use of a database view?

A - It restricts data access.

B - It makes queries easy.

C - It provides data independence.

D - It prevents different views of same data.

Q 9 - Which of the following is not true about the Pseudocolumns that return the sequence values?

A - NEXTVAL returns the next available sequence value.

B - CURRVAL gets the current sequence value.

C - PREVVAL gets the previous sequence value.

D - None of the above.

Q 10 - Which statement is used for allocating system privileges to the users?

A - CREATE

B - GRANT

C - REVOKE

D - ROLE