Question

我正在尝试使用上一页中发布的表单中的PHP会话搜索我的数据库，但搜索不会返回任何语法错误。

Answer 1

试试这个：

$query= "SELECT * FROM students WHERE faculty ='" . $fa. "' AND 
         degree ='" . $de . "' AND course ='" . $co . "' ORDER BY name";

哦，请使用准备好的声明。这个解决方案非常不安全!!

您可以在下面详细了解准备好的声明：

https://www.w3schools.com/php/php_mysql_prepared_statements.asp

Answer 2

首先，免责声明：我不使用mysqli或PDO;我使用自己的数据库抽象。因此，您需要使用文档验证我的示例。

我首先尝试写一个答案，展示mysqli中参数的使用，但坦率地说，mysqli是...... 丑陋。非常丑陋而且相当笨拙。

如果您需要添加会话，则可以在基本原型工作后执行此操作。我没有处理会话，而是解决数据库访问的基础问题。请不要认为这是剪切和粘贴代码：它可能会也可能不会，因为我无法测试它。它旨在为您提供建议和起点。

<?php

//session_start(); // not needed for this example

function get_post($var_name) {
  $out = '';
  if(array_key_exists($var_name,$_POST)) {
    $out = $_POST[$var_name];
  }
  return $out;
}

// whenever you have to do something over, break it out into a function
$faculty = get_post('fac');
$degree  = get_post('degree');
$course  = get_post('course');


// set up PDO connection
// this section credit to https://phpdelusions.net/pdo
$host = '127.0.0.1';
$db   = 'students';
$user = 'root';
$pass = '';
$charset = 'utf8mb4';

$dsn = "mysql:host=$host;dbname=$db;charset=$charset";

// helpful initializations, such as default fetch is associative array
$opt = [
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    PDO::ATTR_EMULATE_PREPARES   => false,
];
$pdo = new PDO($dsn, $user, $pass, $opt);


// note that the first time the page is accessed, 
// the POST variables will be saved as empty strings, 
// so the query will execute fine, but won't find any results.

$query= 'SELECT name,faculty,degree,course,attend ' . 
        'FROM students ' . 
        'WHERE faculty=? AND degree=? AND course=? ' . 
        'ORDER BY name';

$pdo->prepare($query);
$result = $pdo->execute([$faculty, $degree, $course]); // don't miss the [] which is a shortcut for array()

// notice, try to keep PHP and HTML presentation separate,
// with PHP on top. (advanced: learn MVC)
// now that we have access to our data, present the html
// The HTML could be in another file and simply required() here. 

?>
<html>
  <head>
    <title>Staff List</title>
  </head>
  <body>
    <form action="" method="post">
    <img src="login10.png" id="logos"/>
    <h2 id="inf">Staff List </h2>
    <ul>
      <li>
        <label for="fac">Faculty :</label>
        <select id="fac" name="fac" required>
          <option value="">Select course Faculty ..</option>
          <option value="Business">Business</option>
          <option value="Engineering">Engineering</option>
          <option value="pharmaceutical">pharmaceutical</option>
          <option value="Sport">Sport </option>
          <option value="Science">Science </option>
        </select> 
      </li>
      <li>
          <label for="degree">Degree :</label>
        <select id="degree" name="degree" required>
          <option value="">Select Course Degree..</option>
          <option value="Associate degree">Associate degree</option>
          <option value="Bachelor degree">Bachelor degree</option>
          <option value="Master degree">Master degree </option>
          <option value="Doctoral degree">Doctoral degree </option>
        </select> 
      </li>
      <li>
          <label for="course">Required Course :</label>
          <input type="text" name="course" id="course" class="text" placeholder="Enter Course Name" required>

      </li>
      <li>
          <label for="submit">&nbsp;</label>
              <input type="submit" id="submit" value="Student List">
          </li>
      </ul>
    </form> 

    <?php if($faculty && $degree && $course): ?>
      <hr>

      <h2>Results</h2>
      <table>
      <?php while ($row = $result->fetch()): ?>
        <tr class="data"> <!-- can't use id="data" because id has to be unique -->
          <td><?= $row['name'] ?></td>
          <td><?= $row['faculty'] ?></td>
          <td><?= $row['degree'] ?></td>
          <td><?= $row['course'] ?></td>
          <td class="colors"><?= $row['attend'] ?></td>
        </tr>
      <?php endwhile; ?>
      </table>
    <?php endif; ?>
  </body>
</html>

使用php会话搜索数据库不会返回任何结果或错误

2 个答案: