Lesson 17 / 28
HAVING vs WHERE
Filter rows before grouping, or filter groups after.
Filtering groups
WHERE filters rows before grouping; HAVING filters groups after aggregation.
SELECT customer_id, SUM(amount) AS total
FROM orders
GROUP BY customer_id
HAVING SUM(amount) > 2000;Output:
customer_id | total 1 | 3200.00
Can't use WHERE with aggregates
WHERE SUM(amount) > 2000 is invalid — aggregates don't exist yet when WHERE runs. Use HAVING instead.