Fatal error: Uncaught TypeError: mysqli_fetch_assoc(): Argument #1 ($result) must be of type mysqli_result, bool given in C:\xampp\htdocs\cauhinh.php:9 Stack trace: #0 C:\xampp\htdocs\cauhinh.php(9): mysqli_fetch_assoc(false) #1 C:\xampp\htdocs\set.php(3): include_once('C:\\xampp\\htdocs...') #2 C:\xampp\htdocs\index.php(3): include_once('C:\\xampp\\htdocs...') #3 {main} thrown in C:\xampp\htdocs\cauhinh.php on line 9