使用会话 [重复]答案

【问题标题】：Work with Sessions [duplicate]使用会话 [重复]
【发布时间】：2016-01-17 17:50:28
【问题描述】：

我很难理解会话。我想在会话中存储card_id，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";

【问题讨论】：

使用这个 $_SESSION["card_id"] = $card_id;
使用 session_start()、$_SESSION[] 和 PHP 文档 php.net/manual/en/book.session.php
您的示例与会话无关。唯一相关的行（答案的起点）是$card_id =

标签： php mysql sql session mysqli

【解决方案1】：

您可以在整个应用程序中使用$_SESSION。要存储会话，您始终需要以 session_start();

开头

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这个会话变量，例如 test.php：

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

【讨论】：

【解决方案2】：

试试这个代码使用session_start

<?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){

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

        echo "<p>Saldo: $card_id";
        $_SESSION['card_id']=$card_id;
?>

【讨论】：

【解决方案3】：

试试这个：

<?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";
    }
?>

【讨论】：