Typecho获取随机文章函数

function getRandomPosts($random=5){
    $db = Typecho_Db::get();
    $adapterName = $db->getAdapterName();//兼容非MySQL数据库
    if($adapterName == 'pgsql' || $adapterName == 'Pdo_Pgsql' || $adapterName == 'Pdo_SQLite' || $adapterName == 'SQLite'){
        $order_by = 'RANDOM()';
    }else{
        $order_by = 'RAND()';
    }
    $sql = $db->select()->from('table.contents')
        ->where('status = ?','publish')
        ->where('table.contents.created <= ?', time())
        ->where('type = ?', 'post')
        ->limit($random)
        ->order($order_by);

$result = $db->fetchAll($sql);
if($result){
    foreach($result as $val){
        $obj = Typecho_Widget::widget('Widget_Abstract_Contents');
        $val = $obj->push($val);
        $post_title = htmlspecialchars($val['title']);
        $permalink = $val['permalink'];
        echo ''.$post_title.'';
    }
}
}