将 PDO 查询转换为 mySQLi 后未显示结果

Question

我有一个脚本可以从 matieres 和 sous_matieres 两个表中提取数据，但它是为 PDO 编写的，我需要它来为 mySQLi 工作： p>

$stmt = $pdo->query('SELECT 
                        m.id AS m_id, m.url AS m_url, m.title AS m_title, 
                        s.id AS s_id, s.url AS s_url, s.title AS s_title
                     FROM matieres m
                     INNER JOIN sous_matieres s ON m.url = s.parent');

while ($row = $stmt->fetchObject()) {
    $matieres[$row->m_id]['url'] = $row->m_url;
    $matieres[$row->m_id]['title'] = $row->m_title;
    $matieres[$row->m_id]['sous_matieres'][$row->s_id] = $row;
}

foreach ($matieres as $m_id => $matiere) {
    echo "<h2>$matiere[title]</h2>";
    foreach ($matiere['sous_matieres'] as $id => $sm) {
        echo "<div>
                  <a href='{$sm->s_url}'>{$sm->s_title}</a>
              </div>";
    }
}

我的新 mySQLi 代码尽管两个表有数据但什么也没显示：

$query = 'SELECT 
              m.id AS m_id, m.url AS m_url, m.title AS m_title, 
              s.id AS s_id, s.url AS s_url, s.title AS s_title
          FROM matieres m
          INNER JOIN sous_matieres s ON m.url = s.parent';
$stmt = $mysqli->query($query);
$stmt->execute();
$stmt->store_result();

while ($row = $stmt->fetch()) {
    $matieres[$row->m_id]['url'] = $row->m_url;
    $matieres[$row->m_id]['title'] = $row->m_title;
    $matieres[$row->m_id]['sous_matieres'][$row->s_id] = $row;
}

foreach ($matieres as $m_id => $matiere) {
    echo "<h2>$matiere[title]</h2>";
    foreach ($matiere['sous_matieres'] as $id => $sm) {
        echo "<div>
                  <a href='{$sm->s_url}'>{$sm->s_title}</a>
              </div>";
    }
}

我不知道它是否缺少$stmt->bind_result() 和里面的变量。至于普通的 mySQLi 查询（没有连接），我必须在 $stmt->bind_result() 中将选定的列名声明为变量

Answer 1

mysqli_stmt::fetch 用于将变量绑定到准备好的语句的结果以填充这些变量。获取结果的另一种方法是使用 mysqli_result 类，您可以按照您尝试的方式使用它：

$result = $mysqli->query($query);

while ($row = $result->fetch_object()) {
    $matieres[$row->m_id]['url'] = $row->m_url;
    $matieres[$row->m_id]['title'] = $row->m_title;
    $matieres[$row->m_id]['sous_matieres'][$row->s_id] = $row;
}

参见http://php.net/manual/en/mysqli.query.php 和http://php.net/manual/en/class.mysqli-result.php。