Drupal 7 实现上一篇下一篇的简单方法

/**
 * myNodePrevNext
 * 文章上一篇下一篇
 * $nid - 节点id
 * $type - 节点类型
 */
function myNodePrevNext($nid, $type)
{
    $output = '

';

    $sql_previous = "SELECT n.nid, n.title, url.alias "
                  . "FROM {node} AS n "
                  . "LEFT JOIN {url_alias} AS url "
                  . "ON concat('node/',n.nid)=url.source "
                  . "WHERE n.nid < :nid AND n.type = :type "
                  . "ORDER BY n.nid DESC "
                  . "LIMIT 0, 1";

    $result_previous = db_query($sql_previous, array(':nid' => $nid, ':type' => $type));

    $strings = array();

    foreach ($result_previous as $data)
    {
        $data->url = ($data->alias) ? $data->alias : '/node/' . $data->nid;

        $output .= '

• 上一篇：'
                  . ''
                  . $data->title
                  . ''
                  . '
';
    }

    $sql_next = "SELECT n.nid, n.title, url.alias "
              . "FROM {node} AS n "
              . "LEFT JOIN {url_alias} AS url "
              . "ON concat('node/',n.nid)=url.source "
              . "WHERE n.nid > :nid AND n.type = :type "
              . "ORDER BY n.nid ASC "
              . "LIMIT 0, 1";
    $result_next = db_query($sql_next, array(':nid' => $nid, ':type' => $type));

    $strings = array();

    foreach ($result_next as $data)
    {
        $data->url = ($data->alias) ? $data->alias : '/node/' . $data->nid;

        $output .= '

• 下一篇：'
                  . ''
                  . $data->title
                  . ''
                  . '
';
    }

    $output .= '

    return $output;
}