Scriptimiz

SQL Aggregate Function

6.Output of this query?

Table: sales  
id | amount  
1  | 100  
2  | 200  
3  | NULL  

SELECT SUM(amount) FROM sales;

7.What is returned by: If 2 out of 5 products have NULL in price column.

SELECT COUNT(price) FROM products;

8.Which query shows average marks of each subject?

SELECT subject, AVG(marks)  
FROM results  
GROUP BY subject;

9.What does this return?

SELECT MAX(salary) FROM employees;