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Fatal error: Uncaught TypeError: mysqli::query(): Argument #1 ($query) must be of type string, null given in /var/www/html/Klausuren/23WS/Loesung/ExamAPI.php:32 Stack trace: #0 /var/www/html/Klausuren/23WS/Loesung/ExamAPI.php(32): mysqli->query(NULL) #1 /var/www/html/Klausuren/23WS/Loesung/ExamAPI.php(53): ExamAPI->getViewData() #2 /var/www/html/Klausuren/23WS/Loesung/ExamAPI.php(81): ExamAPI->generateView() #3 /var/www/html/Klausuren/23WS/Loesung/ExamAPI.php(89): ExamAPI::main() #4 {main} thrown in /var/www/html/Klausuren/23WS/Loesung/ExamAPI.php on line 32