会话无效

Question

我正在显示数据库中的图片。我可以选择让用户缩短一些图像作为输入。当用户输入一些数字时，照片将根据输入短。

<?php session_start();?>

 <?php
          include "script/db_script.php";
          if(isset($_GET['value1']) && isset($_GET['value2'])){
            $value1 = $_GET['value1'];
            $value2 = $_GET['value2'];
            $_SESSION['value1'] = $_GET['value1'] ;
            $_SESSION['value2'] = $_GET['value2'];
             }
            if(isset($_SESSION['value1']) && $_SESSION['value1']&& 
isset($_SESSION['value2'])&& $_SESSION['value2'] ){
                      $sql =  "SELECT * FROM new_photos WHERE weight BETWEEN 
         $value1 AND $value2";
             anjaan($sql);
             echo "<p>Showing images from $value1 gm to $value2 gm</p>";
             }
             else{
                    $sql='select * from new_photos';
            anjaan($sql);
            echo "<p>Showing all images </p>";}
              ?>

我的表格是

         <form method="GET">
         From  <input style="width: 50px;" name="value1" = type="number"<br>
         To    <input style="width: 50px;" name="value2"type="number"><br>
          <input type="submit" name="submit" value="submit">
                                    </form> 

我的问题是当我点击下一页的分页表格变量而不是设置为会话时。

此代码工作正常

  <?php
    include "script/db_script.php";
        if(isset($_GET['sort'])){
     $_SESSION['sort'] = $_GET['sort'] == '5_15';
     $_SESSION['sort1'] = $_GET['sort'] == '1_10';
        }
            if(isset($_SESSION['sort']) && $_SESSION['sort']){
                    $sql =  'SELECT * FROM new_photos WHERE weight BETWEEN 5 AND 15';
             anjaan($sql);
             echo "<p>Showing images with 5gm to 15gm</p>";
             }
            elseif(isset($_SESSION['sort']) && $_SESSION['sort1']){
                    $sql =  'SELECT * FROM new_photos WHERE weight BETWEEN 1 AND 10';
             anjaan($sql);
             echo "<p>Showing images with 1gm to 10gm</p>";
             }
             else{
                    $sql='select * from new_photos';
            anjaan($sql);
            echo "<p>Showing all images </p>";}
              ?>

表格

            <form method="GET">
                         <select name="sort">
                            <option value="all">All</option>
                             <option value="1_10">1 gm to 10 gm</option>
                             <option value="5_15">5 gm to 15gm</option>
                            </select>
                    <input type="submit" name="submit" value="submit">
                                    </form>   

Answer 1

在使用会话之前，您需要先打开会话：

在任何HTML添加之前的页面顶部：

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