Fatal error: Uncaught PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '-30' at line 1 in /home/erdos/app/app/models/problem_list_model.php:171 Stack trace: #0 /home/erdos/app/app/models/problem_list_model.php(171): PDOStatement->execute(Array) #1 /home/erdos/app/app/controllers/activity_controller.php(11): ProblemListModel::get_submissions('DESC', 30, -30) #2 /home/erdos/app/vendor/torophp/torophp/src/Toro.php(69): ActivityController->get() #3 /home/erdos/app/index.php(120): Toro::serve(Array) #4 {main} thrown in /home/erdos/app/app/models/problem_list_model.php on line 171