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 the distinct honours subjects in the STUDENTS table?

A - select honours_subject from students;

B - select distinct honours_subject from students;

C - select all honours_subject from students;

D - select * from students;

Q 2 - What is returned by TRUNC(789.8389, 2)?

A - 789.84

B - 789.83

C - 78

D - 789.00

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 is not a group function?

A - SUM

B - NVL

C - COUNT

D - MIN

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 - 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 - 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 - 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 code will create an index named stu_marks_ind on the columns student_code and percentage_of_marks of the STUDENTS table?

A - It’s not possible to create an index on two columns.

B - create index stu_marks_ind from students(student_code, percentage_of_marks);

C - create index stu_marks_ind on students(student_code, percentage_of_marks);

D - create index stu_marks_ind (student_code, percentage_of_marks) on students;

Q 10 - Which of the following is true about a role?

A - A role is a named group of related privileges.

B - It can be it can be created and assigned to a user.

C - It can be revoked from a user.

D - All of the above.