如何查询数据库中的IP -错误 - How to query database for an IP - Error

我试图使它，如果他们的IP是在数据库中，然后他们不能发送电子邮件。在php54_errors文件中，它说

[30-Dec-2012 18:25:26 Europe/Dublin] PHP Warning:  mysql_num_rows() expects parameter 1 to be resource, string given in C:'inetpub'wwwroot'Submit.php on line 6
[30-Dec-2012 18:25:26 Europe/Dublin] PHP Warning:  mysql_num_rows() expects parameter 1 to be resource, null given in C:'inetpub'wwwroot'Submit.php on line 7

我的PHP代码如下

<?php
include("connect.php");
mysql_select_db("ip", $con);
$ip = mysql_real_escape_string($_SERVER['REMOTE_ADDR']);
$query = "SELECT * FROM ip WHERE ip='$ip'";
$result = mysql_num_rows($query);
if (mysql_num_rows($result) > 0) {
    echo "You have already registered!";
}
else { 
    echo"Your request has been sent!";
    $to = "admin@prisoneternity.org.uk";
    $subject = "Guard Application";
    $from = "guardapplication@prisoneternity.org.uk";
    $headers = "From:" . $from;
    $message = "IGN = " . $_POST["Username"] . "</br>'n'nage = " . $_POST["age"] . "</br>'n'nreason = " . $_POST["reason"] . "</br>'n'nHow many times have they been guard = " . $_POST["guard"] . "</br>'n'nOther Details = " . $_POST["text"];
    mail($to,$subject,$message,$headers);
    header ("Location: index.php?email=yes");
    session_start();
    mysql_query("INSERT INTO ip (IP) VALUES ('$ip')");
}
?>

$result = mysql_num_rows($query);
if (mysql_num_rows($result) > 0) {

应:

$result = mysql_query($query);
if (mysql_num_rows($result) > 0) {

您没有运行mysql_query()，而是两次调用mysql_num_rows()。简单的事故=o)顺便说一句，你应该使用PDO或MySQLi。

也

echo"Your request has been sent!";
$to = "admin@prisoneternity.org.uk";
$subject = "Guard Application";
$from = "guardapplication@prisoneternity.org.uk";
$headers = "From:" . $from;
$message = "IGN = " . $_POST["Username"] . "</br>'n'nage = " . $_POST["age"] . "</br>'n'nreason = " . $_POST["reason"] . "</br>'n'nHow many times have they been guard = " . $_POST["guard"] . "</br>'n'nOther Details = " . $_POST["text"];
mail($to,$subject,$message,$headers);
header ("Location: index.php?email=yes");
session_start();
mysql_query("INSERT INTO ip (IP) VALUES ('$ip')");

应:

$to = "admin@prisoneternity.org.uk";
$subject = "Guard Application";
$from = "guardapplication@prisoneternity.org.uk";
$headers = "From:" . $from;
$message = "IGN = " . $_POST["Username"] . "</br>'n'nage = " . $_POST["age"] . "</br>'n'nreason = " . $_POST["reason"] . "</br>'n'nHow many times have they been guard = " . $_POST["guard"] . "</br>'n'nOther Details = " . $_POST["text"];
mail($to,$subject,$message,$headers);
//header ("Location: index.php?email=yes");
session_start();
echo"Your request has been sent!";
mysql_query("INSERT INTO ip (IP) VALUES ('$ip')");

你不能回显header()或session_start()之前的内容，也不会看到回显的文本，因为你正在做一个重定向。你需要选择你想做哪一个。我注释掉了上面的header()，但你可以做相反的事情。另外，请确保您清除了'r和'n字符的所有$_POST值，以防止邮件头注入攻击。

在第二行，mysql_num_rows返回一个整数，因为$result变量已经调用了该函数，如果这有意义的话。改成这样:

$result = mysql_num_rows($query);
if ($result > 0) {

同时，您没有运行查询:

$query = "SELECT * FROM ip WHERE ip='$ip'";

把上面的行改成:

$query = mysql_query("SELECT * FROM ip WHERE ip='$ip'");

另一方面，mysql_*函数已弃用。我会切换到PDO或MySQLi -示例可以在PHP手册中找到。