HAVING Filters After GROUP BY

`HAVING` runs after `GROUP BY`. Instead of filtering individual rows, it filters the aggregated groups.

That means this pattern works:

SELECT region, SUM(amount) AS total_amount
FROM sales
GROUP BY region
HAVING SUM(amount) > 2000

SQL first forms one group per region, calculates each total, and only then removes the groups that do not pass the `HAVING` condition.