PhpEd调试器显示变量空值

Question

有谁知道调试器为什么在该脚本中显示$ result和$ mysqli的空值？

<?php 

// show SELECT result as HTML table 
function show_table($result) { 
    if(!$result) { 
    echo "<p>No valid query result.</p>\n"; 
    return; 
    } 

    if($result->num_rows>0 && $result->field_count>0) { 
    echo "<table>"; 

    // column headings 
    echo "<tr>"; 
    foreach($result->fetch_fields() as $meta) 
     printf("<th>%s</th>", htmlspecialchars($meta->name)); 
    echo "</tr>\n"; 

    // content 
    // row fetch row 
    while($row = $result->fetch_row()) { 
     echo "<tr>"; 
     foreach($row as $col) 
     printf("<td>%s</td>", htmlspecialchars($col)); 
     echo "</tr>\n"; 
    } 
    echo "</table>\n"; 
    } 
} 

require_once 'password.php'; 

// connect to MySQL 
$mysqli = new mysqli($mysqlhost, $mysqluser, $mysqlpasswd, $mysqldb); 
if(mysqli_connect_errno()) { 
    echo "<p>Sorry, no connection! ", mysqli_connect_error(), "</p>\n"; 
    exit(); 
} 

// show SELECT result with show_table 
if($result = $mysqli->query("SELECT * FROM titles")) { 
    show_table($result); 
    $result->close(); 
} 

// disconnect 
$mysqli->close(); 

?> 
</body></html> 

<?php 


?> 

Answer 1

哎DOD我想你$ MySQLdb的为null，因为当其空你永远不修改任何错误或警告 我测试它在其他情况下，如没有用户名或密码。
$mysqli = new mysqli($mysqlhost, $mysqluser, $mysqlpasswd, $mysqldb);