Part 22: Multi-Column Sorting & Sorting by Expressions

Sort queries can prioritize multiple columns sequentially.

1. Multi-Column Sorting

-- Sort by Department alphabetically, then by Salary highest to lowest within that department:
SELECT department, last_name, salary 
FROM employees 
ORDER BY department ASC, salary DESC;

2. Sorting by Expressions and Calculations

SELECT item_name, quantity, unit_price
FROM inventory
ORDER BY (quantity * unit_price) DESC;

Key Takeaways

• Database sorts tie-breaks in the order columns are listed in ORDER BY.
• You can sort directly by calculated mathematical expressions.

In Part 23, we will examine Handling NULL Values in Sorting: NULLS FIRST and NULLS LAST!