            $q = self::$mysqli->query($vars) ;
            if($q === false) {
                Control::error('db',"Query failed: ".self::$mysqli->error."<br />\n"); 
            }
        }
        
        return $q;
    }
The software constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.