php - 循环遍历记录集(PHP + MySQL)，将列表项中的每 2 条记录分组

Question

我需要循环遍历一个记录集(PHP + MySQL)，将每 2 条记录分组到一个列表项中

我的实际代码(简化)是这样的:

<?php
// how many total records do I have?
mysql_select_db($database_connEIB, $connEIB);
$query_rsMediaCount = "SELECT COUNT(*) AS med_count FROM media";
$rsMediaCount = mysql_query($query_rsMediaCount, $connEIB) or die(mysql_error());
$row_rsMediaCount = mysql_fetch_assoc($rsMediaCount);

$mCount = $row_rsMediaCount['med_count']; // total records
$mPages = ceil($mCount / 2); // max LIs to create
$mIndex = 0; // useful initialization for LIMIT, see below

if ($mCount > 0) { // let's show markup only if there's some record!
?>
    <ul>
    <?php for ($mPage = 1; $mPage <= $mPages; $mPage++) { // create the LIs ?>
        <li>
        <?php
        $query_rsMedia = "SELECT med_id FROM media LIMIT $mIndex, 2";
        $rsMedia = mysql_query($query_rsMedia, $connEIB) or die(mysql_error());
        $row_rsMedia = mysql_fetch_assoc($rsMedia);
        do { ?>
            <div><?php echo $row_rsMedia['med_id']; ?></div>
        <?php } while ($row_rsMedia = mysql_fetch_assoc($rsMedia));
        $mIndex += 2; // increment the LIMIT by 2 steps ?>
        </li>
    <?php } ?>
    </ul>
<?php } ?>

输出排序如下:

<ul>
    <li>
        <div>1</div>
        <div>2</div>
    </li>
    <li>
        <div>3</div>
        <div>4</div>
    </li>
    <li>
        <div>5</div>
    </li>
</ul>

一切正常，但是有没有更优雅或更有效的解决方案？提前致谢

Answer 1

仅执行一次查询并将结果分组在循环内。使用模运算符%:

$query_rsMedia = "SELECT med_id FROM media";
$rsMedia = mysql_query($query_rsMedia, $connEIB) or die(mysql_error());

if (mysql_num_rows($rsMedia) > 0) { // check if there is at least one result
    echo '<ul>';
    $index = 0;
    while ($row_rsMedia = mysql_fetch_assoc($rsMedia)) {
        if ($index % 2 == 0) echo '<li>'; // open <li> bevore even result
        echo '<div>'.$row_rsMedia['med_id'].'</div>';
        if ($index % 2 == 1) echo '</li>'; // close <li> after odd result
        $index++;
    }
    if ($index % 2 == 1) echo '</li>'; // close <li> if odd result count
    echo '</ul>';
}

(只是写的，不是测试)