Quiz on SQL Aggregate Functions

What does the SQL SUM() function return?

Which function returns the total number of non-NULL rows in a column?

What does AVG() return?

Which function gives the smallest value in a column?

What does MAX() return?

What will COUNT(*) return?

What is the result of this query?

SELECT COUNT(DISTINCT department_id) FROM employees;

What will this query return?

SELECT SUM(salary) FROM employees WHERE department_id = 10;

Can aggregate functions ignore NULL values by default?

Which clause is most commonly used with aggregate functions?

What will `AVG(NULL)` return?

Which function will return the total number of employees regardless of NULLs?

What is the result of using SUM() on a VARCHAR column?

Which aggregate function can be used with the HAVING clause?

What does the following query return?

SELECT MAX(salary) – MIN(salary) FROM employees;