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 all the students whose first name starts with the character ‘A’?

A - select first_name from students where first_name like ‘A%’;

B - select first_name from students where first_name like ‘%A’;

C - select first_name from students where first_name like ‘%A%’;

D - select first_name from students where first_name like ‘A’;

Q 2 - Which of the following is not a character manipulation function?

A - concat

B - substr

C - instr

D - coalesce

Q 3 - Which of the following is true about Cartesian Products?

A - A Cartesian product is formed when a join condition is omitted.

B - A Cartesian product is formed when a join condition is valid.

C - Some rows in the first table are joined to all rows in the second table.

D - All rows in the first table are joined to some rows in the second table.

Q 4 - Consider the following schema −

HONOURS_SUBJECT(subject_code, subject_name, department_head);

LOCATIONS(subject_code, department_name, location_id, city);

Select the right query for retrieving records from the tables HONOURS_SUBJECT and LOCATIONS with a full outer join

A - select h.subject_name, l.department_name, h.department_head, l.city from honours_subject h full outer join location l on(h.subject_code = l.subject_code);

B - select h.subject_name, l.department_name, h.department_head, l.city from honours_subject h full outer join location l on(subject_code);

C - select h.subject_name, l.department_name, h.department_head, l.city from honours_subject h full outer join location l where (h.subject_code = l.subject_code);

D - None of the above.

Q 5 - You want to calculate the sum of commissions earned by the employees of an organisation. If an employee doesn’t receive any commission, it should be calculated as zero. Which will be the right query to achieve this?

A - select sum(nvl(commission, 0)) from employees;

B - select sum(commission, 0) from employees;

C - select nvl(sum(commission), 0) from employees;

D - None of the above.

Q 6 - Which of the following is not true about modifying rows in a table?

A - Existing rows in a table are modified using the UPDATE statement.

B - You can update more than one row at a time.

C - All the rows in a table are modified if you omit the WHERE clause.

D - None of the above.

Q 7 - Which of the following is NOT true about the SQL transaction control statements?

A - The COMMIT statement ends the current transaction and makes all data changes permanent.

B - The ROLLBACK statement ends the transaction and discards all the pending data changes.

C - Each DML statement is automatically committed.

D - All are true.

Q 8 - Which of the following is not true about creating constraints?

A - Constraints are defined using the CREATE CONSTRAINT statement.

B - They are created at the same time when the table is created.

C - They could be created after the table is created.

D - All the constraints are stored in data dictionary.

Q 9 - Which of the following code will delete a sequence named loc_seq?

A - delete sequence loc-seq;

B - drop sequence loc_seq;

C - delete primary key loc_sec;

D - drop primary key loc_sec;

Q 10 - Which of the following is a system privilege?

A - Creating new users

B - Removing users

C - Removing tables

D - All of the above.