使用会话

Question

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";

Answer 1

您可以在整个申请过程中使用$_SESSION。 要存储会话，您始终需要从session_start();

开始

如果我们看一下你的例子：

<?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

Answer 2

请尝试使用此代码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;
?>

Answer 3

尝试使用：

<?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";
    }
?>