Need to get data from php db?

Question

PHP

The error gets out... how it is better to make request?

$quer = mysqli_query($link, "SELECT * FROM `product` WHERE `where_is` = 'product' AND `ctg` = " . (int) $_GET['sub'] . AND `sub_ctg` = (int) $_GET['id_sub']);

Answer 1

Your quotes are missing in the second part of the query. I think if you learned how to use syntax highlighting here (and at the same time in your editor), you would notice it.
And I also really, really recommend pumping the most powerful skill of reading error log.