Hello! I am trying to make a combination between two combobox, where a third one shows the list with the products that contains the category and the brand, but when I do not have any product registered with the two attributes, I would like it to show some alert saying that there is no product registered with these attributes, but I did not find the right way to do it!
I can not explain the situation very well, but I hope you understand kkkk I will attach the images with the code and the error that appears when I post information that has no product. The database I use is MySQL, if it helps.
Here the product exists with the attribute "category" and "brand":
