php - while 循环中的 mysql_fetch_array 在本地主机中工作，但在主机服务器中不工作

Question

$result = mysql_query('SELECT * FROM phpfox_education_question where subject_id = 2 and ques_id =1');
var_dump($result);
//var_dump result is :- "resource(64) of type (mysql result)" in localhost and web host,but
while($row = mysql_fetch_array($result))
{
    var_dump($row); //**NOTHING DISPLAYED in web host server but in localhost**
}

Answer 1

尝试添加这个：

var_dump(mysql_num_rows($result));

要查看是否有要获取的行，如果没有，这就是您的答案。
顺便说一句，在 PDO 中，此代码如下所示：

$db = new PDO('mysql:dbname=default_db_name;host=127.0.0.1',$user,$pass);
//use prepared statmenets
$stmt = $db->prepare('SELECT * FROM your_db.phpfox_education_question WHERE subject_id = :subject_id AND ques_id = :ques_id');
//pass binds when executing the stmt
$stmt->execute(array(':subject_id' => 2, ':ques_id' => 1));
//number of rows found:
var_dump($stmt->rowCount());
while($row = $stmt->fetch(PDO::FETCH_ASSOC))
{//fetch rows as assoc array
    var_dump($row);
}

请注意，这是一个基本示例，您可以使用 PDO 做更多事情

更新：
要获得更多调试信息，试试这个：

try
{
    $db = new PDO();//connect, pass correct data here
    $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);//cause PDO to throw PDOExceptions on error
    $stmt = $db->prepare('SELECT * FROM your_db.phpfox_education_question WHERE subject_id = :subject_id AND ques_id = :ques_id');
    $stmt->execute(array(':subject_id' => 1, ':ques_id' => 2));
    var_dump($stmt->rowCount());
    while($row = $stmt->fetch(PDO::FETCH_ASSOC))
    {
        var_dump($row);
    }
}
catch(PDOException $e)
{
    echo $e->getMessage();
    $db = null;
    return;
}
echo 'No problems with query<br/>';
$db = null;//disconnecto

确保没有抛出错误，如果有，检查消息，找出问题所在并修复它。如果您找不到修复它们的方法，我们当然会为您提供帮助。

Answer 2

试试这个：

$query = "SELECT * FROM phpfox_education_question WHERE subject_id = '2' AND ques_id = '1'";
$result = mysql_query($query) or die(mysql_error()); // <--- added this
echo "Results: ".mysql_num_rows($result)."<br />"; // <--- added this to output result count
while($row = mysql_fetch_array($result))
{
    print_r($row); //**NOTHING DISPLAYED in web host server but in localhost**
}

这是使用的折旧代码 btw