发布变量返回无效

Question

I am using a simple PHP script for the activation part of one of my applications. The applications posts one variable to the page (http://validate.zbrowntechnology.info/WebLock.php?method=validate). The variable is the serial number, posted as 'Serial'. Each time I post to this page, it returns Invalid. Here is the code:

<?php

$serial = $_POST['Serial'];
$method = $_GET['method'];

$con = mysql_connect("HOSTHERE", "USERHERE", "PASSHERE");
if(!$con) {
  die('Unable to connect to MySQL:  ' . mysql_error());
}


if($method == "validate") {

  mysql_select_db("zach_WebLock", $con);

  $query = "SELECT Key, Status FROM Validation WHERE Key='".mysql_real_escape_string($serial)."'";
  $result = mysql_query($query);
  if(mysql_num_rows($result) > 0) {
    echo "Valid";
  } else {
    echo "Invalid";
  }
} else {
  echo "Unkown Method";
}
?>

Here Is The Error From PHP,

PHP Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given

Answer 1

Right after the query use mysql_error() to see what happened. And Key is a bad choice for a column name because it's a reserved word in SQL. You can enclose it in `` to tell MySQL it's an identifier. Do some more debugging like this:

...
if (!mysql_select_db("zach_WebLock", $con)) die('mysql_select_db failed');

$query = "SELECT `Key`, Status FROM Validation WHERE `Key`='".mysql_real_escape_string($serial)."'";
print "query=$query<br>
";
$result = mysql_query($query, $con);
print "error=" . mysql_error($con);
...