How do you order or sort by multiple columns in SQL?

To order or sort by multiple columns in SQL, you can use the ORDER BY clause and specify the columns you want to sort by, separated by commas. You can also define the sorting order (ascending ASC or descending DESC) for each column. For example:

SELECT * FROM employees
ORDER BY department ASC, salary DESC;

This query will first sort by the department column in ascending order, and if there are multiple employees in the same department, it will then sort them by salary in descending order. You can include as many columns as needed for sorting.