Question

我有一个包含以下记录的表：

product_id | title   | category
------------------------------------
1          | apple   | mobile
2          | android | mobile
3          | dell    | desktop
4          | hp      | desktop

以及以下查询：

$sql = "SELECT product_id, title, category FROM products ORDER BY category"; 
$stmt = $db->prepare($sql); 
$stmt->execute(); 
  while($results = $stmt->fetch(PDO::FETCH_ASSOC)) 
{ 
echo $results["product_id"];
echo $results["title"];
echo $results["category"];
}

问题是如何拆分结果并显示按类别排序的列表中的所有记录，如下所示：

移动
Apple
Android

桌面

戴尔
HP

Answer 1

获取结果集后对记录进行分组：

$products = array();

while ($results = $stmt->fetch(PDO::FETCH_ASSOC)) 
{ 
    $products[$results['category']][] = array(
        'product_id' => $results['product_id'],
        'title'      => $results['title']
    );
}

foreach ($products as $category => $productList)
{
    echo $category . '<br>';

    foreach ($productList as $product)
    {
        echo $product['title'] . '<br>';
    }

    echo '<hr />';
}

Answer 2

使用SELECT * FROM products GROUP BY category ORDER BY title

Answer 3

在对商品（ORDER BY category, title）进行排序后，请执行以下操作：

$last_category = "";
while(/* get a row here */) {
    if( $last_category != $row['category']) {
        if( $last_category != "") echo "</ul>";
        echo "<ul>";
        $last_category = $row['category'];
    }
    echo "<li>".$row['title']."<li>";
}
if( $last_category != "") echo "</ul>";

Answer 4

SELECT * FROM产品ORDER BY类别。这是使用类别排序，您的示例输出文件似乎与您尝试做什么不同？

按类别对项目排序

4 个答案: