具有一个或多个（多个）参数的搜索表单

我已经掌握了基础知识，在其中创建了两个文件：用户输入搜索参数的搜索表单，以及生成输入项目的结果文件。为了简单起见，我们将搜索表单文件指定为 search.php，将结果页面指定为 results.php。

搜索.php

<?php
    
if (!empty($_POST['id']) && isset($_POST['id'])) {
    header("Location: ?m=search.results&id=".$_POST['id']."");
} elseif (!empty($_POST['major']) && isset($_POST['major'])) {
    header("Location: ?m=search.results&major=".$_POST['major']."");
} elseif (!empty($_POST['college']) && isset($_POST['major'])) {
    header("Location: ?m=search.results&college=".$_POST['college']."");
} elseif (!empty($_POST['name']) && isset($_POST['name'])) {
    header("Location: ?m=search.results&name=".$_POST['name']."");
} elseif (!empty($_POST['id']) && !empty($_POST['college']) && !empty($_POST['major'])
                            && isset($_POST['submit']) && !empty($_POST['name'])) {
    echo "<div class='alert alert-danger'>No students found. Please try different parameters.</div>";
}

?>


<h4>Search</h4>

<form method="POST">
    <table width="100%">

<tr><td>ID:</td><td> <input type="text" name="id" class="form-control"></textarea></td></tr>

<tr><td>Name:</td><td> <input type="text" name="name" class="form-control"></textarea></td></tr>

<tr><td>Major:</td><td><select name="major" class="form-control"><option></option><?php echo majorSelect(); ?></select></td></tr>

    <tr><td>College:</td><td><select name="college" class="form-control"><option></option><?php echo collegeSelect(); ?></select></td></tr>

<tr><td colspan="2"><input type="submit" name="submit" value="Search" class="btn btn-lrg btn-primary" style="margin-top:10px;"></td></tr>

    </table>
</form>

结果.php

<!-- Begin Search Parameters -->

<?php

if (isset($_GET['id'])) {
    $students = $db->query("SELECT * FROM `user_details` a, `user` b WHERE a.uid = b.id AND a.uid = '".$_GET['id']."'");
    
    while ($student = $students->fetch()) {
        echo '
            <tr>
                <td>'.$student['uid'].'</td>
                <td>'.$student['name'].'</td>
                    <td>'.$student['major'].'</td>
                    <td>'.$student['college'].'</td>
                <td><a href="?m=profile&id='.$student['id'].'" style="display:block">View</a></td>
                
            </tr>';
    }
} elseif (isset($_GET['major'])) {
    $students = $db->query("SELECT * FROM `user_details` a, `user` b WHERE a.uid = b.id AND a.major = '".$_GET['major']."'");
        
    while ($student = $students->fetch()) {
        echo '
            <tr>
                <td>'.$student['uid'].'</td>
                <td>'.$student['name'].'</td>
                    <td>'.$student['major'].'</td>
                    <td>'.$student['college'].'</td>

                <td><a href="?m=profile&id='.$student['id'].'" style="display:block">View</a></td>
                
            </tr>';
    }
} elseif (isset($_GET['college'])) {
    $students = $db->query("SELECT * FROM `user_details` a, `user` b WHERE a.uid = b.id AND a.college = '".$_GET['college']."'");
        
    while ($student = $students->fetch()) {
        echo '
            <tr>
                <td>'.$student['uid'].'</td>
                <td>'.$student['name'].'</td>
                    <td>'.$student['major'].'</td>
                    <td>'.$student['college'].'</td>
                <td><a href="?m=profile&id='.$student['id'].'" style="display:block">View</a></td>
                
            </tr>';
    }
} elseif (isset($_GET['name'])) {
    $name = $_GET['name'];
        
    $students = $db->query("SELECT * FROM `user_details` a, `user` b WHERE a.uid = b.id AND b.name LIKE '%". $name . "%'");
        
    while ($student = $students->fetch()) {
        echo '
            <tr>
                <td>'.$student['uid'].'</td>
                <td>'.$student['name'].'</td>
                    <td>'.$student['major'].'</td>
                    <td>'.$student['college'].'</td>
                <td><a href="?m=profile&id='.$student['id'].'" style="display:block">View</a></td>
                
            </tr>';
    }
}    

因此，本质上我想重写上述内容，而用户可以输入一个或多个参数，并返回所需的结果（例如姓名和大学 - &name=x&college=y 或所有项目（如果需要））。

当使用 PDO（而不是 mysqli）作为数据库 API 时，这是最容易做到的。

构建WHERE动态条款。我推荐的方法是将每个条件推入一个数组，然后使用implode()连接所有条件，将它们与AND or OR这是您的偏好。

$wheres = array();
$params = array();
if (!empty($_GET['id'])) {
    $wheres[] = 'a.uid = :uid';
    $params[':uid'] = $_GET['id'];
}
if (!empty($_GET['major'])) {
    $wheres[] = 'a.major = :major';
    $params[':major'] = $_GET['major'];
}
if (!empty($_GET['name'])) {
    $wheres[] = 'b.name LIKE :name';
    $params[':name'] = '%'.$_GET['name'].'%';
}
// And so on for all parameters

$sql = "SELECT * 
        FROM user_details AS a
        JOIN user AS b ON a.uid = b.id";
if (!empty($wheres)) {
    $sql .= " WHERE " . implode(' AND ', $wheres);
}
$stmt = $db->prepare($sql);
$stmt->execute($params);

然后按照原始代码显示结果。

while ($student = $stmt->fetch()) {
    ...
}