php - PDO 分页在显示第一个结果后不显示数据

Question

我正在尝试创建一个分页页面，该页面每页仅显示搜索查询的一个结果，但在显示第一个结果后，下一个结果或页面将给我一个没有输入有效输入的错误

 <?php
    define("ROW_PER_PAGE",1);
    $search = '';
      if (!empty($_POST['search'])) {
         $search = $_POST['search'];

                  /* Search Entry */

                $keywords =  explode(' ', $search);
                $arr_length = count($keywords);
                $sub_query = '';

                    for ($i = 0; $i < $arr_length; $i++) {
                      if ($i == 0) {
                        $sub_query = $sub_query . 'sym_body LIKE "%' . $keywords[$i] . '%" OR sym_tags LIKE "%' . $keywords[$i] . '%"';
                        }else {
                        $sub_query = $sub_query . ' OR sym_body LIKE "%' . $keywords[$i] . '%" OR sym_tags LIKE "%' . $keywords[$i] . '%"';
                      }
                    }

                  /* Query */
                $query = 'SELECT * FROM symptoms WHERE ' . $sub_query; 


                  /*Pagination Code Starts */
                        $per_page_htm = '';
                        $page = 1;
                        $start = 0;
                          if(!empty($_GET['r'])) {
                             $page = $_GET['r'];
                             $start = ($page - 1) * ROW_PER_PAGE;
                           }     
                  $limit = "LIMIT " . $start . "," . ROW_PER_PAGE;

                /* Getting Row Count Tested Working */
              $p_query = 'SELECT COUNT(*) FROM symptoms WHERE ' . $sub_query;
              $pag_stnt = $con->query($p_query);
              $row_count = $pag_stnt->fetchColumn();

                echo "<h4>You have $row_count result(s)</h4>";

                    if (!empty($row_count)) {
                      $per_page_htm .= "<div style='text-align:center;margin:20px 0px;'>";
                      $page_count = ceil($row_count / ROW_PER_PAGE);
                        if ($page_count > 1) {
                          $self = $_SERVER['PHP_SELF'];
                            for($i=1; $i<=$page_count; $i++){
                                if($i==$page){
                                    $per_page_htm .= "<a href='".$self."?r=".$i."' class='btn-page current'>".$i."</a>";
                                  }else{
                                    $per_page_htm .= "<a href='".$self."?r=".$i."' class='btn-page'>".$i."</a>"; 
                                }
                            }
                        }
                        $per_page_htm .= "</div>";




                          $n_query = 'SELECT * FROM symptoms WHERE ' . $sub_query . ' '.$limit ;

                            foreach ($con->query($n_query) as $row) {

                              $sym_cat_id = $row['cat_id'];
                              $sym_pro = $row['sym_pro'];

                              $sym_body = $row['sym_body'];
                              $sym_ans = $row['sym_answer'];



                      ?>
                    <!-- Symptom Area-->

                      <div class="panel-group results">
                          <div class="panel panel-success">
                            <div class="panel-heading">
                             <p><?php //echo $cat_title;?></p> 
                             <?php echo $search; ?>
                            </div>
                            <div class="panel-body">
                              <?php echo $sym_body; ?>
                              <p><h4>Answer</h4>
                              <?php echo $sym_ans;?></p>
                              <p><h4>Was the answer helpful</h4></p>

                                  <p>
                                    <a href="index.php" class="btn btn-info pull-left"> Yes</a>
                                    <button type="button" class="btn btn-danger pull-right">No</button>
                                  </p>
                            </div>
                          </div>
                      </div>
                          <?php
                            }
                         }else{  
                        echo '<script>
                            setTimeout(function(){
                              swal({
                                title: "Sorry!",
                                text: "Your Query is not in our database",
                                type: "info"

                              }, function(){
                                window.location = "index.php";
                              });
                            }, 1000);
                            </script>';}
              echo $per_page_htm;
         }else{
            echo '<script>
              setTimeout(function(){
                swal({
                  title: "Oops!",
                  text: "Please enter a valid value!",
                  type: "error"

                }, function(){
                  window.location = "index.php";
                });
              }, 1000);
          </script>';} ?>

Answer 1

... after displaying the first result, the next result or page will give me an error that no valid input was inputted

那是因为当您点击第 2、3、... 页时(从第 1 页导航之后)，$_POST 数组将为空，即 $_POST['search' ] 不会被设置。由于您没有使用表单发送任何敏感数据，因此在表单的 method 属性中使用 GET 而不是 POST ，如下所示:

<form action="..." method="get">

并像这样获取用户输入的数据:

if (!empty($_GET['search'])) {
    $search = $_GET['search'];
    ...

随后，您需要在每个分页链接中附加该搜索查询，以便在您从一个页面跳到另一个页面时可以使用该搜索查询。

// your code
for($i=1; $i<=$page_count; $i++){
    if($i==$page){
        $per_page_htm .= "<a href='".$self."?r=".$i."&search=".urlencode($search)."' class='btn-page current'>".$i."</a>";
    }else{
        $per_page_htm .= "<a href='".$self."?r=".$i."&search=".urlencode($search)."' class='btn-page'>".$i."</a>"; 
    }
}
// your code

---

旁注:了解 prepared statement因为现在您的查询很容易受到 SQL 注入(inject)攻击。另见 how you can prevent SQL injection in PHP .