mysql how to specify condition on an aggregated column?

Question

I have a table with order id, product id and the quantity of each product of that order (like in the table below). And I have to select the order_id and it's total quantity where the quantity is more than 5.

+----------+------------+----------+
| order_id | product_id | quantity |
+----------+------------+----------+
|        1 |          1 |        6 |
|        1 |          2 |        1 |
|        2 |          3 |        3 |
|        2 |          2 |        2 |
|        3 |          1 |        3 |
|        3 |          3 |        5 |
+----------+------------+----------+

What I've tried is

SELECT order_id, SUM(quantity) AS qty
FROM order_product
WHERE qty > 5 /* <-- Cannot use qty here */
GROUP BY order_id;

ERROR 1054 (42S22): Unknown column 'qty' in 'where clause'

AFAIK the where clause executed before summing the quantity columns so I cannot use qty there but is there any way to run the condition after the aggregation or is there any other way to solve it?

Answer 1

To filter after aggregation, you can use a HAVING clause.

SELECT order_id,
       sum(quantity) AS qty
       FROM order_product
       GROUP BY order_id
       HAVING sum(quantity) > 5;