Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, null given in /var/www/html/lecturer/content/cont.sdg_banner.php:13 Stack trace: #0 /var/www/html/lecturer/content/cont.sdg_banner.php(13): mysqli_query() #1 /var/www/html/lecturer/content/cont.sdg_banner.php(61): project_count() #2 /var/www/html/lecturer/sdg.php(43): include('...') #3 {main} thrown in /var/www/html/lecturer/content/cont.sdg_banner.php on line 13