            $q = self::$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.