PHP Form Validator/MySQL Insert

Question

I have written a small PHP file that gets the information that was posted to it, then checks to make sure it is no empty. If it isn't empty, it checks to make sure the username doesn't already exist. If it does, it redirects. If not, it adds the information to the MySQL database. I don't know what the problem is, but when attempting to navigate to it after pressing the submit button on the form, the browser displays an error saying that the page cannot be displayed. Here is the code.

<?php
$firstname = $_POST['fname'];
$lastname = $_POST['lname'];
$email = $_POST['email'];
$username = $_POST['user'];
$password = $_POST['pass'];


$con = mysql_connect("localhost","USER","PASS");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("zach_blogin", $con);

$query="SELECT username FROM members WHERE username=$username";



if (mysql_num_rows($username) > 0 ) {
  header("Location: register.php?invalid");
} else {
  $sql=("INSERT INTO members (username, password, FirstName, LastName, Email)
  VALUES ($username, $password, $firstname, $lastname, $email)");
  if (!mysql_query($sql,$con))
    {
    die('Error: ' . mysql_error());
    }
else {
  header("Location: register.php?required");
}
?>

codaddict · Accepted Answer · 2010-09-24 04:34:20Z

5

You are not executing the query:

$query="SELECT username FROM members WHERE username=$username";
//You need to execute the query here before you get num of rows.
if (mysql_num_rows($username) > 0 ) // also mysql_num_query takes an object.

Something like:

$query="SELECT username FROM members WHERE username=$username";
if(($result = mysql_query($query)) !== false) {
  if (mysql_num_rows($result) > 0 ) {
   .....
  }
}

answered Sep 24, 2010 at 4:34

codaddict

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2 Comments

Zac Brown Over a year ago

I have tried both solutions, but the script is still not working. Maybe another error in my script?

Zac Brown Over a year ago

Ok, sorry. I figured it out... I had a typo. I am however having a problem. I used your ( @codaddict ) script there, but now when the username is already taken, it just displays a message saying duplicate entry.... I need it to redirect to register.php?invalid

Pramendra Gupta · Accepted Answer · 2010-09-24 04:52:37Z

2

Change this

if (mysql_num_rows($username) > 0 ) {

to

if (mysql_num_rows(mysql_query($query)) > 0 ) {

answered Sep 24, 2010 at 4:52

Pramendra Gupta

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4 Comments

codaddict Over a year ago

Its always better to check the return value of mysql_query before you proceed. That makes debugging easier.

Pramendra Gupta Over a year ago

thats right but i think something wrong in one line , so lets give solution on that wrong line , if it works

Zac Brown Over a year ago

I have tried both solutions, but the script is still not working. Maybe another error in my script?

Pramendra Gupta Over a year ago

can you post in jsfillde.net and share url, i can advise further

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