相当于PDO的Mysqli

Question

我正在尝试将mysqli转换为PDO：

$product_id = $_GET['p'];
$product_query = "SELECT * FROM products,categories WHERE product_cat=cat_id AND product_id BETWEEN $product_id AND $product_id+3";
$run_query = mysqli_query($con,$product_query);
      if(mysqli_num_rows($run_query) > 0){
            while($row = mysqli_fetch_array($run_query)){
                        $pro_id    = $row['product_id'];
                        $pro_cat   = $row['product_cat'];
                        $pro_brand = $row['product_brand'];
                        $pro_title = $row['product_title'];
                        $pro_price = $row['product_price'];
                        $pro_image = $row['product_image'];
                        $cat_name = $row["cat_title"];

我的尝试没有用，我的问题是我不确定mysqli_num_rows与PDO是什么等效：输出应获得相似类别列表之间的产品，以显示为电子商务网站的相关产品

$query = $connect->prepare("SELECT * FROM product WHERE prd_cat = cat_id AND prd_id BETWEEN :product_id AND :product_id+3");
$query->execute(['product_id' => $_GET['p']]);
        while ($row = $query->fetchAll()){
                        $pro_id    = $row['prd_id'];
                        $pro_cat   = $row['prd_cat'];
                        $pro_brand = $row['prd_brand'];
                        $pro_title = $row['prd_name'];
                        $pro_price = $row['prd_price'];
                        $pro_image = $row['prd_image'];

                        $cat_name = $row["cat_title"];

                        echo "

感谢任何人都可以提供帮助，我仍在尝试学习php和mysql，但我已经阅读到数据库的PDO功能比mysqli更好。

Answer 1

实际上，您也不需要为mysqli计算行数。这个功能没用。

首先，选择所有数据作为数组。

$sql = "SELECT * FROM product WHERE id BETWEEN ? AND ?";
// There is likely a problem in your SQL so I removed the `prd_cat = cat_id ` part
$stmt = $connect->prepare($sql);
$stmt->execute([$_GET['p'], $_GET['p'] + 3]);
$data = $stmt->fetchAll();

然后简单地遍历此数组：

foreach($data as $row)
{
    $pro_id    = $row['prd_id'];
    $pro_cat   = $row['prd_cat'];
    $pro_brand = $row['prd_brand'];
    $pro_title = $row['prd_name'];
    $pro_price = $row['prd_price'];
    $pro_image = $row['prd_image'];
    $cat_name = $row["cat_title"];
}

Answer 2

$query = $connect->prepare("SELECT * FROM product WHERE prd_cat = cat_id AND prd_id BETWEEN :product_id1 AND :product_id2");
$query->execute(['product_id1' => $_GET['p'], 'product_id2' => ($_GET['p'] + 3)]);
if($query->rowCount() > 0)
{
    $data = $query->fetchAll(\PDO::FETCH_ASSOC);
    foreach($data as $row)
    {
        $pro_id    = $row['prd_id'];
        $pro_cat   = $row['prd_cat'];
        $pro_brand = $row['prd_brand'];
        $pro_title = $row['prd_name'];
        $pro_price = $row['prd_price'];
        $pro_image = $row['prd_image'];

        $cat_name = $row["cat_title"];
    }
}