I\'m pretty sure this is not possible in Zend Framework (I have searched the Web, the documentation and issue tracker) but I just want to make sure so I\'m asking here.
The best way Zend suggest is like follows....
$sql = $this->_db->select()
->union(array($select1, $select2,$select3))
->order('by_someorder');
echo $sql->__toString();
$stmt = $db->query($sql);
$result = $stmt->fetchAll();
echo will show the query
Here $select1, $select2, $select3 can be different select queries with same number of columns...