这个：
$select = $db->select()->from(array("s" => "sles"), array("s.id","i.id as instanceid","i.reference","i.name","i.sic_pre","i.start_date"))->join(array('i' => "sle_instances"),"s.id = i.sle_id",array())->where("i.id = (select max(id) from sle_instances where sle_id = s.id)")->order('i.name asc');给出以下内容：
"SELECt `s`.`id`, `i`.`id` AS `instanceid`, `i`.`reference`, `i`.`name`, `i`.`sic_pre`, `i`.`start_date` FROM `sles` AS `s` INNER JOIN `sle_instances` AS `i` ON s.id = i.sle_id WHERe (i.id = (select max(id) from sle_instances where sle_id = s.id)) ORDER BY `i`.`name` asc"
