Column does not exist error when using Having clause-CodePudding

I'm following along the steps in this article and am having trouble with the following query:

SELECT Quantity, COUNT(*) AS Quantity_Counts
FROM sqlbank3
WHERE UnitPrice >= 5
GROUP BY Quantity
HAVING Quantity_Counts < 450
ORDER BY Quantity_Counts DESC
LIMIT 10;

ERROR: column "quantity_counts" does not exist

LINE 5: HAVING Quantity_Counts < 450

I put everything in lower case to see if that did anything but to no avail. I have created Quantity as an integer. The query runs when I remove the HAVING clause so it's certainly finding the Quantity_Counts column, just not with the HAVING clause. Any help is appreciated.

CodePudding user response：

The HAVING clause is supposed to be evaluated before the SELECT clause. You cannot use the alias defined in SELECT in HAVING for that reason.

You must use

HAVING COUNT(*) < 450

instead.

(Some DBMS allow it to use alias names in the HAVINGclause, though.)