SUM, AVG, MIN, MAX

SUM(column) adds a column up, AVG averages it, MIN and MAX find the smallest and largest. Several can share one query: SELECT SUM(stock), AVG(price) FROM products; returns one row with both numbers. NULLs are ignored by all of them.

Mixing an aggregate with a plain column, SELECT name, MAX(price), is a classic mistake: SQLite returns the name from the max row, other databases refuse. The right tool for "which product is the most expensive" is ORDER BY price DESC LIMIT 1 or a subquery.

SELECT MIN(salary), MAX(salary), AVG(salary) FROM employees;

Your task

In one query on products, show the total stock, the average price, the lowest price, and the highest price, in that order.

SELECT SUM(stock), AVG(price), MIN(price), MAX(price) FROM products;