Php 与会话一起工作

我很难理解这些课程。我想在会话中存储卡片，我该怎么做

$resultSet = $mysqli->query ("SELECT value FROM card_credit 
WHERE card_id= (select distinct card_id 
                from Raw where 
                 id = (select max(b.id) from Raw as b))");

if($resultSet->num_rows != 0){

while($rows = $resultSet->fetch_assoc())
    {
        $card_id = $rows['value'];

        echo "<p>Saldo: $card_id";

请尝试使用会话启动此代码

您可以在整个应用程序中使用$\u会话。 要存储会话，您始终需要从会话\u start开始

如果我们看看你的例子：

<?php
session_start();
$resultSet = $mysqli->query ("SELECT value FROM card_credit 
                WHERE card_id= (select distinct card_id 
                from Raw where 
                 id = (select max(b.id) from Raw as b))");

if($resultSet->num_rows != 0){

while($rows = $resultSet->fetch_assoc())
    {
        $card_id = $rows['value'];
        $_SESSION['card_id'] = $card_id; //Set session variable
        echo "<p>Saldo: $card_id";
    }

现在，我们可以在另一个页面上使用此会话变量，例如test.php：

 <?php 
 session_start();
 echo $_SESSION['card_id']; //Echo's the id

尝试使用以下方法：

<?php
    // Start the session
    session_start();

    $resultSet = $mysqli->query ("SELECT value FROM card_credit WHERE card_id= (select distinct card_id from Raw where id = (select max(b.id) from Raw as b))");

    if($resultSet->num_rows != 0){
        $card_id = $rows['value'];
        // Set session variables
        $_SESSION["card_id"] = $card_id;
        //echo "Session variables are set.";
        echo "<p>Saldo: $card_id";
    }
?>

---

使用此$\u会话[card\u id]=$card\u id；使用session\u start、$\u session[]和PHP文档，您的示例与session无关。答案的唯一相关行起点是$card\u id=

<?php
    // Start the session
    session_start();

    $resultSet = $mysqli->query ("SELECT value FROM card_credit WHERE card_id= (select distinct card_id from Raw where id = (select max(b.id) from Raw as b))");

    if($resultSet->num_rows != 0){
        $card_id = $rows['value'];
        // Set session variables
        $_SESSION["card_id"] = $card_id;
        //echo "Session variables are set.";
        echo "<p>Saldo: $card_id";
    }
?>