Question

我正在尝试使用不同的下拉过滤器（成绩，学校，团队，学生）实施搜索，但我的代码出现了严重问题。当我加载页面“retrieve1.php”时，我只能看到一个框，即等级，也是空的。我将不胜感激任何帮助。以下是我的代码 -

SLOC

account1.php

<?php
require 'account1.php';
echo "<body style='background-color:#DCDCDC'>";

$sql= "SELECT * FROM bpi_registration LEFT JOIN bpi_schoolInfo on 
bpi_registration.id_school = bpi_schoolInfo.id_school ";
$query=$db->query($sql);


function grade() {
    $result = $db->query('SELECT * FROM bpi_classInfo');
    while($row = $result->fetchALL(PDO::FETCH_ASSOC))
    {
        echo "<option value='" . $row['class_name'] . "'>" . $row['class_name'] . "</option>";
    }
}

function school() {
    $result = $db->query('SELECT * FROM bpi_schoolInfo');
    while($row = $result->fetchALL(PDO::FETCH_ASSOC))
    {
        echo "<option value='" . $row['school_name'] . "'>" . $row['school_name'] . "</option>";
    }
}

function team() {
    $result = $db->query('SELECT * FROM bpi_teamProfile');
    while($row = $result->fetchALL(PDO::FETCH_ASSOC))
    {
        echo "<option value='" . $row['team_name'] . "'>" . $row['team_name'] . "</option>";
    }
}

function students() {
    $result = $db->query('SELECT * FROM bpi_registration');
    while($row = $result->fetchALL(PDO::FETCH_ASSOC))
    {
        echo "<option value='" . $row['id']. "'>" . $row['first_name'].' '.$row['last_name']. "</option>"; 
    }
}
?>

<form action="retrieve1.php" method="GET">
    <select name="Grade">
        <option value="" selected="selected">Choose Grade</option>
        <?php grade() ?>
    </select>

    <select name="School">
        <option value="" selected="selected">Choose School</option>
        <?php school() ?>
    </select>

    <select name="Team">
    <option value="" selected="selected">Choose Team</option>
    <?php team() ?>
    </select>

    <select name="Students">
        <option value="" selected="selected">Choose Students</option>
        <?php students() ?>
    </select>

    <input type="submit" value="Find" />
</form>

<table width="600" border="2">  
    <tr>  
        <th width="198"> <div align="center">Email </div></th>  
        <th width="97"> <div align="center">City </div></th>  
        <th width="97"> <div align="center">State </div></th>  
        <th width="59"> <div align="center">Country </div></th>   
    <tr>


<?php
if (isset($_GET['Students'])) 
{
    //echo $_GET['Students'];
    $userQuery = "{$sql} WHERE bpi_registration.id = :user_id";
    $user = $db->prepare($sql);
    $user->execute(['user_id' => $_GET['Students']]);
    $selectedUser=$user->fetch(PDO::FETCH_ASSOC);
}
?>

<?php
if(isset($selectedUser))
{
    echo $selectedUser['email'];
    echo $selectedUser['address_city']; 
    echo $selectedUser['address_state']; 
    echo $selectedUser['address_country']; 
}
?>

我收到错误

<?php
$db = new PDO('mysql:host=localhost;dbname=test',$user, $pass);
?>

Answer 1

您报告的错误是由于变量范围问题造成的。换句话说，函数不知道$db是什么，因为它超出范围，$db存在于全局范围内，但不存在于每个函数范围内。

同样，->FetchAll()将返回一个数组，如果您使用while循环来处理查询中的结果集，则应使用->fetch()，因为这将每次调用返回一行并可用于一段时间循环。

此外，您运行的第一个查询，然后稍后尝试修改搜索条件将无效。调用->query()后，无法修改查询。因此，我将该代码移动到实际使用的位置，并删除了对->query()

的不必要调用

我还在输出中添加了一些表格行HTML，以便数据适合表格结构。

下面修改后的代码应该会让您朝向目标或下一个错误。

<?php
require 'account1.php';
echo "<body style='background-color:#DCDCDC'>";

function grade($db) {
    $result = $db->query('SELECT * FROM bpi_classInfo');
    while($row = $result->fetch(PDO::FETCH_ASSOC))
    {
        echo "<option value='" . $row['class_name'] . "'>" . $row['class_name'] . "</option>";
    }
}

function school($db) {
    $result = $db->query('SELECT * FROM bpi_schoolInfo');
    while($row = $result->fetch(PDO::FETCH_ASSOC))
    {
        echo "<option value='" . $row['school_name'] . "'>" . $row['school_name'] . "</option>";
    }
}

function team($db) {
    $result = $db->query('SELECT * FROM bpi_teamProfile');
    while($row = $result->fetch(PDO::FETCH_ASSOC))
    {
        echo "<option value='" . $row['team_name'] . "'>" . $row['team_name'] . "</option>";
    }
}

function students($db) {
    $result = $db->query('SELECT * FROM bpi_registration');
    while($row = $result->fetch(PDO::FETCH_ASSOC))
    {
        echo "<option value='" . $row['id']. "'>" . $row['first_name'].' '.$row['last_name']. "</option>"; 
    }
}
?>

<form action="retrieve1.php" method="GET">
    <select name="Grade">
        <option value="" selected="selected">Choose Grade</option>
        <?php grade($db) ?>
    </select>

    <select name="School">
        <option value="" selected="selected">Choose School</option>
        <?php school($db) ?>
    </select>

    <select name="Team">
    <option value="" selected="selected">Choose Team</option>
    <?php team($db) ?>
    </select>

    <select name="Students">
        <option value="" selected="selected">Choose Students</option>
        <?php students($db) ?>
    </select>

    <input type="submit" value="Find" />
</form>

<table width="600" border="2">  
    <tr>  
        <th width="198"> <div align="center">Email </div></th>  
        <th width="97"> <div align="center">City </div></th>  
        <th width="97"> <div align="center">State </div></th>  
        <th width="59"> <div align="center">Country </div></th>   
    </tr>


<?php
if (isset($_GET['Students'])) 
{
    $sql= "SELECT * 
           FROM bpi_registration 
             LEFT JOIN bpi_schoolInfo on 
                       bpi_registration.id_school = bpi_schoolInfo.id_school ";


    //echo $_GET['Students'];
    $userQuery = "{$sql} WHERE bpi_registration.id = :user_id";
    $user = $db->prepare($sql);
    $user->execute(['user_id' => $_GET['Students']]);
    $selectedUser=$user->fetch(PDO::FETCH_ASSOC);

    if(isset($selectedUser))
    {
        echo '<tr>';
        echo '<td>' . $selectedUser['email'] . '</td>';
        echo '<td>' . $selectedUser['address_city'] . '</td>'; 
        echo '<td>' . $selectedUser['address_state'] . '</td>'; 
        echo '<td>' . $selectedUser['address_country'] . '</td>'; 
        echo '</tr>
    }
}
echo '</table>`;
?>

获取数据问题

1 个答案: