php - 选择第n页而不是第n页

我有一个网页可以从我的MySQL数据库分页结果。以下代码用于创建下拉菜单来浏览结果。目前已设置为选择第n页；假设（例如）当我请求第30页时，相关记录存储在结果集的第30行，但是经过一些测试，显然不是这种情况。我应该如何改变它，使其返回第n页呢？我知道这是while语句，需要调整，但我只是不太清楚。

    //…previous code…

    $rowsPerPage = 1;

    // by default we show first page
    $pageNum = 1;

    // if $_GET['page'] defined, use it as page number
    if(isset($_GET['page']))
    {
        $pageNum = $_GET['page'];
    }

    $offset = ($pageNum - 1) * $rowsPerPage;

    $query3 = 'SELECT t1.s_name AS t1_sname, t1.uh_heading AS t1_unit, t1.ut_latin AS t1_latin, t1.ut_english AS t1_english, t1.uh_id, t1.chapter_sequence AS t1_chapters, t1.unit_sequence AS t1_units,
                      t2.s_name AS t2_sname, t2.ut_latin AS t2_latin, t2.ut_english AS t2_english, t2.chapter_sequence AS t2_chapters, t2.unit_sequence AS t2_units
               FROM vw_source_text_and_translation AS t1
               LEFT JOIN vw_source_text_and_translation AS t2
               ON (t2.uh_id = t1.uh_id AND t2.s_id = " ' . $_SESSION['source2'] . ' " )
               WHERE t1.s_id =  " ' . $_SESSION['source1'] . ' "
               ORDER BY t1.chapter_sequence, t1.unit_sequence' .
               " LIMIT $offset, $rowsPerPage";

//...more code...

    $query4   = 'SELECT uh_id, chapter_sequence, unit_sequence, uh_heading
             FROM vw_source_text_and_translation
             WHERE s_id = "' . $_SESSION['source1'] . '"';

//...more code...

    $rows= $result4;
    $numrows = 0;
    $nav  = '';
    while ($row = mysql_fetch_assoc($rows))
    {
      $nav .= ' <option value="'. $row['uh_id'] .'"> '.
              $row['chapter_sequence'] .'.'.$row['unit_sequence'] .
              ' - '. $row['uh_heading'] .'</option>';
      $numrows ++;
    }

    /*…more code… */

好的，因此在某些帮助下，此问题已部分修复； while语句现在显示为：

while ($row = mysql_fetch_assoc($rows))
 {
  $numrows ++;
  $nav .= ' <option value=" ' . $numrows . '"> '. $row['chapter_sequence'] .'.'.
             $row['unit_sequence'] .' - '. $row['uh_heading'] .'</option>';
 }

这解决了分页问题，​​尽管我仍然存在一些记录无法显示的问题，即使我在MySQL Toolkit中以$ _SESSION ['source1']和$ _SESSION ['source2']的设置值运行$ query3时，也可以正常工作。似乎如果t2.ut_latin或t2.ut_english的值为NULL，则即使它识别出已分页的记录，也不会显示任何数据。但是，我认为这超出了这个问题的主题，因此我可能不得不在一个新问题中重新发布。

最佳答案

您应该使用带有偏移量的LIMIT子句。

SELECT col1, col2, col3
FROM yourtable
ORDER BY something
LIMIT 40, 10

要计算偏移量，请将页码（从0开始）乘以每页的行数。