How to calculate the total cost of orders using an SQL query?

To calculate the total cost of orders in SQL, the aggregate function SUM is usually used. Suppose you have a table orders with a column order_amount storing the cost of each order. The query would look like:

SELECT SUM(order_amount) AS total_order_cost
FROM orders;

This query returns the sum of all values in the order_amount column, i.e., the total cost of all orders.