Fatal error: Uncaught Error: Call to a member function num_rows() on boolean in /var/www/html/application/models/main_model.php:182 Stack trace: #0 /var/www/html/application/controllers/Main_controller.php(66): main_model->get_sub_categories(Array) #1 /var/www/html/system/core/CodeIgniter.php(359): Main_controller->view('Computers', 'Laptop%20Access...', 'Pen%20drives') #2 /var/www/html/index.php(303): require_once('/var/www/html/s...') #3 {main} thrown in /var/www/html/application/models/main_model.php on line 182