php 使用上一页中的参数选择查询

Question

我想从数据库中查询一些内容，但它根本不返回任何值。我想知道为什么它没有报告任何错误。请检查附件。

这是我编写的代码。谢谢。

echo '<form method = "post" action = "http://localhost:8080/nbm/delivery/show_delivery_details.php">';

$nbm = new Db();

$poid = $_GET['id'];// this was taken from the previous page
echo $poid;//tried to display this and it does

 $get_deliveries= $nbm->query("SELECT * FROM `customer_order_list` where purchase_order_id = '$poid'");

    foreach($get_deliveries as $key){
     echo $key['purchase_order_id'].'&nbsp;&nbsp;'.$key['customer_id'].'&nbsp;&nbsp;'.$key['amount'];

   }

print_r($get_deliveries);//also tried this but it displays nothing

echo '</form>';

Answer 1

  $nbm->query("SELECT * FROM `customer_order_list` where purchase_order_id = '".$poid."'");