ORDER BY Before or After GROUP BY?

The short answer

GROUP BY comes before ORDER BY — no exceptions. This is true two ways at once: it's the required syntax order, and it's the logical execution order. Group the rows, then sort the groups.

-- ✅ Group first, then sort the grouped result
SELECT department, COUNT(*) AS headcount
FROM employees
GROUP BY department
ORDER BY headcount DESC;

-- ❌ Syntax error: ORDER BY cannot come before GROUP BY
SELECT department, COUNT(*)
FROM employees
ORDER BY department
GROUP BY department;

Written order vs execution order

SQL requires clauses in a fixed sequence, and evaluates them in a different (but consistent) sequence. In both, GROUP BY precedes ORDER BY:

Since ORDER BY runs after SELECT, it can "see" everything the query has already produced — grouped columns, aggregates, and aliases. For the full pipeline, see SQL execution order explained.

What you CAN sort by after GROUP BY

In a grouped query, ORDER BY may reference:

• Any column in the GROUP BY list (e.g. ORDER BY department).
• Any aggregate (e.g. ORDER BY COUNT(*) DESC, ORDER BY SUM(amount)).
• Any alias defined in SELECT (e.g. ORDER BY headcount).
• An ordinal position (e.g. ORDER BY 2) — though naming the column or alias is clearer.

Sorting by an aggregate (top-N groups)

Sorting by an aggregate is how you build "top N" reports. Combine it with LIMIT:

-- Five departments with the most employees
SELECT department, COUNT(*) AS headcount
FROM employees
GROUP BY department
ORDER BY COUNT(*) DESC
LIMIT 5;

Note that LIMIT runs after ORDER BY, so it correctly takes the top 5 of the sorted result — not five random groups.

Sorting by a SELECT alias

Because ORDER BY is evaluated after SELECT, aliases you created there are available — the opposite of WHERE, which runs before SELECT and can't see them.

SELECT department, AVG(salary) AS avg_salary
FROM employees
GROUP BY department
ORDER BY avg_salary DESC;   -- alias works in ORDER BY

What you can't ORDER BY

The grouping rule applies to ORDER BY too: a column that isn't in GROUP BY and isn't aggregated has no single value per group, so you can't sort by it.

-- ❌ salary isn't grouped or aggregated
SELECT department, COUNT(*)
FROM employees
GROUP BY department
ORDER BY salary;

-- ✅ Sort by an aggregate of salary instead
SELECT department, COUNT(*)
FROM employees
GROUP BY department
ORDER BY AVG(salary) DESC;

GROUP BY doesn't sort

A frequent assumption is that GROUP BY returns groups in sorted order "for free." It doesn't — grouping and sorting are separate operations, and the order you happen to get can change with indexes or engine versions. If you need a specific order, always add ORDER BY. (More on this in GROUP BY mistakes that break SQL queries.)

Full clause order reference