Interview Questions

1. Does COUNT(*) include NULL values?

Options:

a. Yes

b. No

Reveal Answer

2. Does AVG function consider NULL values?

Options:

a. Yes

b. No

Reveal Answer

3. The functions COUNT(), MIN() and MAX() cannot take as input which of the following data type?

Options:

a. int

b. char

c. decimal

d. date

Reveal Answer

4. Can grouping be done on multiple columns

Options:

a. Yes

b. No

Reveal Answer

5. Which of the following statement is used to alias the column Empname as Employeename?

Options:

a. Select Empname AS EmployeeName from Employee

b. Select Empname Employeename from Employee

c. Only a

d. Both a and b

Reveal Answer

6. Query to get all employees belonging to department 10 and 20

Options:

a. Select * from employee where deptid IS EQUAL TO 10 OR 20

b. Select * from employee where deptid =10 AND deptid=20

c. Select * from employee where deptid IN(10,20)

d. None

Reveal Answer

7. Aggregate functions can return?

Options:

a. only multiple values

b. only single value

c. either single value or multiple values

Reveal Answer

8. Which of the following is not a aggregate function

Options:

a. Sum

b. With

c. Min

d. Avg

Reveal Answer

9. Aggregate functions can be used in the select list or the_ clause of a select statement or subquery. They cannot be used in a clause.

Options:

a. Where,Having

b. Having,Where

c. Groupby,Having

d. Groupby, where

Reveal Answer

10. Which of the following function is used for calculating aggregate value.

Options:

a. Sum

b. Max

c. Average

d. Avg

Reveal Answer

11. Which of the following queries can be used for calculating average salary of all the employees.

Options:

a. Select avg(salary) from Employees

b. Select avg(salary) as‘avgsal' from Employees

c. Select avg(salary)‘avgsal’ from Employees

d. All are correct

Reveal Answer

12. Which of the following queries will return max salary of all employees, whose names are starting with character K

Options:

a. Select max(salary) from employees where name=’k%’

b. Select max(salary) from employees where salary=’k%’

c. Select max(salary) from employees where salary like ’%k%’

d. Select max(salary) as ‘maxsal’ from employees where name like ‘k%’

Reveal Answer

13. Which of the following queries will display total salaries of all the employees.

Options:

a. Select total(salary) from employees

b. Select sum(salary) from employees

c. Select total of salary from employees

d. Select sum of salary from employees

Reveal Answer

14. Which of the following queries will display min salaries of all db department employees

Options:

a. Select sum(salary) from employees where dept=’db’

b. Select min(salary) from employees where dept=’db’

c. Select min(salary) from employees where dept like ‘db’

d. None of the above

Reveal Answer

15. What is the use of count function in sql

Options:

a. Count function used only for displaying total number of columns present in the original result set

b. Count function used for displaying total number of rows present in the result set

c. Count function used for displaying total number of columns present in the result set

d. None of the above

Reveal Answer

16. Which of the following queries will display top or maximum salary from employees

Options:

a. Select top(salary) from employees

b. Select top of salary from employees

c. Select Maximun(salary) from employees

d. Select max(salary) from employees

Reveal Answer

17. The HAVING clause is added to SQL because the WHERE keyword cannot be used with aggregate functions.

Options:

a. True

b. False

Reveal Answer

18. An SQL statement with the Having clause may or may not include the ............ clause

Options:

a. Group By

b. Select

c. From

d. All of above

Reveal Answer

19. Similar to the WHERE clause, the HAVING clause requires that the column names that appear in the clause must also appear as column names in the GROUP BY clause.

Options:

a. True

b. False

Reveal Answer

20. Select dept_name, ID, avg (salary) from instructor group by dept_name This statement is erroneous because

Options:

a. Avg(salary) should not be selected

b. Dept_id should not be used in group by clause

c. Misplaced group by clause

d. Group by clause is not valid in this query

Reveal Answer

Interview Questions and Answer

1. Does COUNT(*) include NULL values?

2. Does AVG function consider NULL values?

3. The functions COUNT(), MIN() and MAX() cannot take as input which of the following data type?

4. Can grouping be done on multiple columns

5. Which of the following statement is used to alias the column Empname as Employeename?

6. Query to get all employees belonging to department 10 and 20

7. Aggregate functions can return?

8. Which of the following is not a aggregate function

9. Aggregate functions can be used in the select list or the_ clause of a select statement or subquery. They cannot be used in a clause.

10. Which of the following function is used for calculating aggregate value.

11. Which of the following queries can be used for calculating average salary of all the employees.

12. Which of the following queries will return max salary of all employees, whose names are starting with character K

13. Which of the following queries will display total salaries of all the employees.

14. Which of the following queries will display min salaries of all db department employees

15. What is the use of count function in sql

16. Which of the following queries will display top or maximum salary from employees

17. The HAVING clause is added to SQL because the WHERE keyword cannot be used with aggregate functions.

18. An SQL statement with the Having clause may or may not include the ............ clause

19. Similar to the WHERE clause, the HAVING clause requires that the column names that appear in the clause must also appear as column names in the GROUP BY clause.

20. Select dept_name, ID, avg (salary) from instructor group by dept_name This statement is erroneous because

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