API class to grab info in the database using a sql query sent trough the URL

api.php

//API
    public static function get_list($table,$displayType,$fields=NULL,$complement=NULL) {//Default = JSON
       try {               
               $db=new db();
               
               if(isset($fields) && isset($complement)){
                    $db->sql = "SELECT $fields FROM $table $complement;";                   
               }
               else{                   
                    $db->sql = "SELECT * FROM $table;";
               }
               
               //die($db->sql);
               
               $stmt = $db->conn->prepare($db->sql); 
               $stmt->execute();
               $result = $stmt->fetchAll(PDO::FETCH_NAMED);
                
               //die($displayType);
                
                if($displayType=="json"){
                    return json_encode($result);
                }
                else{    
                    return print_r($result);
                }
                
                  
       }// End of try
       catch(PDOException $e){
            echo $e->getMessage();     
            $this->conn = null;
            die();
        }// End of catch
    }