Fatal error: Uncaught TypeError: Argument 1 passed to DBOperationMySQLi::getString4Sql() must be of the type string, null given, called in /home/www/Relaunch_ELBE/classes/db/DBWorkDozenten.php on line 1526 and defined in /home/www/Relaunch_ELBE/classes/dboperation/DBOperationMySQLi.php:499 Stack trace: #0 /home/www/Relaunch_ELBE/classes/db/DBWorkDozenten.php(1526): DBOperationMySQLi->getString4Sql(NULL) #1 /home/www/Relaunch_ELBE/classes/export/ExportCalculation.php(12058): DBWorkDozentenWB->getDozentenGruppiert(NULL, '1/21,1/22,1/23,...', '1') #2 /home/www/Relaunch_ELBE/classes/export/ExportGruppiert.php(15): ExportCalculation->getVarValue4LetterList('doz_uebersicht', '') #3 /home/www/Relaunch_ELBE/classes/exportadapter/Exportadapter.php(373): ExportGruppiert->getVarValue('ll_doz_uebersic...') #4 /home/www/Relaunch_ELBE/classes/exportadapter/ExportadapterVariableProviderAdapter.php(41): Exportadapter->getVarValue('ll_doz_uebersic...') #5 /home/www/Relaunch_ELBE/classes/scripting/ScriptingEngineHTMLScript2.php(149): Kufer in /home/www/Relaunch_ELBE/classes/dboperation/DBOperationMySQLi.php on line 499