SELECT   taskId, name 
FROM      tasks 
WHERE   taskId = (SELECT MAX(taskId) FROM  tasks);

public function getLastTaskForId($data)
{
    $select = Zend_Db_Table::getDefaultAdapter()->query(
    "SELECT taskId, name 't.name'
     FROM tasks
     WHERE categoryId = $data and taskId = (SELECT max(taskId) FROM tasks WHERE categoryId = $data)")->fetchAll();

    return $select[0];
}