    public function getDigits($key, $default = '')
    {
        // we need to remove - and + because they're allowed in the filter
        return str_replace(array('-', '+'), '', $this->filter($key, $default, FILTER_SANITIZE_NUMBER_INT));
    }
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.