SQL ORDER BY Explained

Quick answer

ORDER BY sorts the rows returned by a query. If you do not use ORDER BY, SQL does not guarantee the order of the results.

• ASC means ascending order, like A to Z or lowest to highest
• DESC means descending order, like Z to A or highest to lowest

In this guide

Sample table

Imagine this employees table:

Why ORDER BY matters

Without ORDER BY, the database can return rows in whatever order is convenient internally. That order may look stable at first, but you should not rely on it.

In real work, sorting matters because you often want:

• highest salary first
• alphabetical customer lists
• newest records first
• top-performing categories at the top of a report

Ascending order

Ascending order goes from smallest to largest for numbers, and usually A to Z for text.

SELECT name, salary
FROM employees
ORDER BY salary ASC;

This sorts salaries from lowest to highest.

Descending order

Descending order goes from largest to smallest for numbers, and usually Z to A for text.

SELECT name, salary
FROM employees
ORDER BY salary DESC;

This sorts salaries from highest to lowest.

Sort by multiple columns

You can sort by more than one column. SQL applies the sort from left to right.

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

This means:

• first sort by department alphabetically
• then sort by salary highest to lowest within each department

Text vs number sorting

Sorting numbers and text follows different logic:

For example:

SELECT name, department
FROM employees
ORDER BY name ASC;

That would sort names alphabetically: Ana, Ben, Chris, Dana, Evan.

Use ORDER BY with GROUP BY

ORDER BY is often used after GROUP BY so you can sort summaries.

SELECT department, COUNT(*) AS employee_count
FROM employees
GROUP BY department
ORDER BY employee_count DESC;

This sorts departments by employee count from highest to lowest.

How NULL values behave

NULL values can behave differently depending on the database engine, but they are usually treated as missing values rather than normal text or numbers.

In many systems:

• NULL values may appear first in descending order
• NULL values may appear last in ascending order

Common mistakes

• forgetting to use DESC when you want highest values first
• assuming results will stay in a specific order without ORDER BY
• sorting by the wrong column
• not understanding that multi-column sorts are applied from left to right
• thinking the database will automatically know the “best” order

Practice questions

Bottom line

ORDER BY controls how query results are sorted. That makes it one of the most important finishing steps in a SQL query.

Once you understand ascending, descending, and multi-column sorting, your query results become much easier to read and much more useful.

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