Вы можете сделать следующее:
$db = Zend_Db_Table::getDefaultAdapter();
$select = $db->select();
$select->from('advertisercontest', '*')
->joinLeft(
'advertiseraccount',
'advertiseraccount.loginid = advertisercontest.loginid',
array('advertiseraccount.advertiserid', 'advertiseraccount.companyname')
)
->where('advertisercontest.golive is not NULL');;
$result = $db->fetchAll($select);
var_dump($result);
Вот документация Zend_Db_Select .