Fatal error: Uncaught TypeError: mysqli_num_rows(): Argument #1 ($result) must be of type mysqli_result, bool given in /home/jksung/public_html/acad280/ddxPractice1.php:17 Stack trace: #0 /home/jksung/public_html/acad280/ddxPractice1.php(17): mysqli_num_rows(false) #1 {main} thrown in /home/jksung/public_html/acad280/ddxPractice1.php on line 17