src/Request.php
public function getQuery($key = null, $default = null) {
        if ($key === null) {
            return $this->env['QUERY'];
        }
        return isset($this->env['QUERY'][$key]) ? $this->env['QUERY'][$key] : $default;
    }
public function getQuery($key = null, $default = null) {
        if ($key === null) {
            return $this->env['QUERY'];
        }
        return isset($this->env['QUERY'][$key]) ? $this->env['QUERY'][$key] : $default;
    }
Get an item from the query string array.

@param string|null $key Either a string key or null to get the entire array.
@param mixed|null $default The default to return if {@link $key} is not found.
@return string|array|null Returns the query string value or the query string itself.
@see Request::setQuery()