Order Of Execution of the SQL query exception for SELECT/HAVING - sql

Question

I understand that the order or execution is as follows
FROM
ON
JOIN
WHERE
GROUP BY
WITH CUBE or WITH ROLLUP
HAVING
SELECT
DISTINCT
ORDER BY
TOP
from this SO Answer as well as Microsoft Documentation
However, in my query below, the column total is built on the fly which is later used in having clause. This would mean that having executes AFTER select and not before because the column 'total' does not exist in orders table.
Am I interpreting it wrong or simply missing something?
Query
select customer_id,
sum(CASE
WHEN product_name = 'A' THEN 1
WHEN product_name = 'B' THEN 1
WHEN product_name = 'C' THEN -1
ELSE 0 END
) as total
from Orders
group by customer_id
having total > 1;
Orders table
+------------+-------------+--------------+
| order_id | customer_id | product_name |
+------------+-------------+--------------+
| 10 | 1 | A |
| 20 | 1 | B |
| 30 | 1 | D |
| 40 | 1 | C |
| 50 | 2 | A |
| 60 | 3 | A |
| 70 | 3 | B |
| 80 | 3 | D |
| 90 | 4 | C |
+------------+-------------+--------------+
Result
+-------------+-------+
| customer_id | total |
+-------------+-------+
| 3 | 2 |
+-------------+-------+

Answer 1

What you have described is NOT the "order of execution". It is the order of scoping for identifiers defined in the query.
It is saying that an identifier defined in from is known in the clauses beneath it. Similarly, an identifier defined in the select is not recognized in the having. I should note that many databases do allow the having clause to use aliases in the having clause. SQL Server is not one of them.
SQL is a descriptive language, not a procedural language. That means that a query describes the result set. It does not state the steps used to generate the result. The compiler and optimizer produce the execution plan, which looks nothing like the original query.