zend framework怎么进行三表查询

zend framework如何进行三表查询
请教zend framework如何进行三表查询，两表查询小弟试过了可以
$adapater = Zend_Db_Table::getDefaultAdapter();  
$select = $adapater->select();
$select->from('course','*');
$select->join('menu','menu.mid=course.categoryid','name');

请教三表查询的问题，希望给位高手解答。

[解决办法]

$select = $db->select();
$select->from(array('p' => 'person'), array('person_id', 'name', 'dob'))
->join(array('pa' => 'Person_Address'), 'pa.person_id = p.person_id', array())
->join(array('a' => 'Address'), 'a.address_id = pa.address_id', array('address_id', 'street', 'city', 'state', 'country'));