数据存储在Session中，但在其他php文件中提取时，某些对象为null - Data stored in Session but when fetch in other php file some objects is null

Data stored in Session but when fetch in other php file some objects is null

在我将数据存储在会话数组中的原始数据上，当我提取它时，所有数据都是完整的，但当我在另一个会话上调用该会话时，一些数据为null或未定义。

我不知道该怎么办，请帮助

编辑：在原始文件中

$query = $dbh->prepare("Select p.start_date,p.end_date,dfp.id,dfp.product_id
      dfp.type,dfp.quantity_required,dfp.less,pd.unit,pd.name
      from promo p
      inner join discounts_free_products dfp                        
      on p.id=dfp.promo_id                        
      inner join products pd                        
      on dfp.product_id=pd.id                       
      where DATE(p.end_date) >= DATE(NOW()) 
");
$query->execute();
$count=0;
$queryresult_set=array();
$queryresult_set=$query->fetchAll();
$count=count($queryresult_set); 
$_SESSION['COUNT_PROMO']= $count;
$_SESSION["PROMO_PRODUCTS"]=$queryresult_set;

在其他php文件中

foreach($_SESSION["PROMO_PRODUCTS"] as $result) { 
    $pc_list[] = $result["product_id"]; 
    $d_id=$result['id']; 
}

错误：未定义的索引：product_id

PHP 5会话

使用session_start()函数启动会话

会话创建

<?php
    // Start the session
    session_start();
?>
<!DOCTYPE html>
<html>
<body>
<?php
    // Set session variables
    $_SESSION["favcolor"] = "green";
    $_SESSION["favanimal"] = "cat";
?>
</body>
</html>

在另一页上检索会话

<?php
    session_start();
?>
<!DOCTYPE html>
<html>
<body>
<?php
    // Echo session variables that were set on previous page
    echo "Favorite color is " . $_SESSION["favcolor"] . ".<br>";
    echo "Favorite animal is " . $_SESSION["favanimal"] . ".";
?>
</body>
</html>

您可能忘记在文件开头添加session_start();。这是我刚开始工作时最常见的问题。但如果没有你的代码，这里没有人能帮你。

编辑：你确定你有：
original.php

session_start();
$query = $dbh->prepare("Select p.start_date,p.end_date,dfp.id,dfp.product_id
          dfp.type,dfp.quantity_required,dfp.less,pd.unit,pd.name
          from promo p
          inner join discounts_free_products dfp                        
          on p.id=dfp.promo_id                        
          inner join products pd                        
          on dfp.product_id=pd.id                       
          where DATE(p.end_date) >= DATE(NOW()) 
");
$query->execute();
$count=0;
$queryresult_set=array();
$queryresult_set=$query->fetchAll();
$count=count($queryresult_set); 
$_SESSION['COUNT_PROMO']= $count;
$_SESSION["PROMO_PRODUCTS"]=$queryresult_set;

并且在other.php中

session_start();
foreach($_SESSION["PROMO_PRODUCTS"] as $result) { 
        $pc_list[] = $result["product_id"]; 
        $d_id=$result['id']; 
}

编辑
尝试：

session_start();
foreach($_SESSION["PROMO_PRODUCTS"] as $result) {
    if (isset($_SESSION["PROMO_PRODUCTS"]))
       if ($_SESSION["PROMO_PRODUCTS"] != NULL){
          $pc_list[] = $result["product_id"]; 
          $d_id=$result['id']; 
          echo $_SESSION["PROMO_PRODUCTS"];                   
       }
    }
}

也许你有饼干，但错过了在别的地方填。这是来自<a href="http://stackoverflow.com/questions/18731693/undefined-index-with-php-sessions">here</a>。