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 - What is returned by MOD(1000,30)?

A - 33

B - 30

C - 3

D - 10

Q 3 - Which of the following is true about SQL joins?

A - The join condition is not separated from other search conditions in a query.

B - The ON clause makes code difficult to understand.

C - The join condition for natural join is basically an equijoin of all columns with same name.

D - None of the above.

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 left outer join

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

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

D - None of the above.

Q 5 - Which of the following is not true about the COUNT function?

A - COUNT(*) returns the number of rows in the table.

B - COUNT(exp) returns the number of rows with non-null values for the exp.

C - COUNT(DISTINCT exp) returns the number of unique, non-null values in the column.

D - All are true.

Q 6 - Which of the following is true about removing rows from a table?

A - You remove existing rows from a table using the DELETE statement

B - No rows are deleted if you omit the WHERE clause.

C - You cannot delete rows based on values from another table.

D - All of the above.

Q 7 - A transaction starts when

A - A COMMIT statement is issued

B - A ROLLBACK statement is issued

C - A CREATE statement is used

D - All of the above

Q 8 - 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 code will create a simple view named all_marks_english that contains the names and percentage of marks of the students in the honours_subject ‘Eng01’?

A - create view all_marks_english as select first_name, last_name, percentage_of_marks from students where honours_subject = ‘Eng01’;

B - create view all_marks_english as ( first_name, last_name, percentage_of_marks from students where honours_subject = ‘Eng01’);

C - select view all_marks_english as select first_name, last_name, percentage_of_marks from students where honours_subject = ‘Eng01’;

D - None of the above.

Q 9 - Which of the following is not true about a sequence?

A - They are used for generating sequential numbers.

B - Sequences are created by the CREATE SEQUENCE statement.

C - You cannot modify a sequence.

D - None of the above.

Q 10 - Which of the following is not true about database synonyms?

A - Synonyms are used for shortening lengthy object names.

B - A synonym is just an alternative name.

C - Synonyms can be created for tables, views, sequences, procedures and other database objects.

D - None of the above.