How to check duplicate entry in registration form?

[Pikachu2000]

No, it isn't a bug. A string value used as an array index needs to be quoted. If left unquoted, php interprets it as a constant, just like it would do with any other unquoted string value. Don't believe me? Turn on error reporting (since it should be on while you're developing anyhow), and see for yourself.

 

error_reporting(-1);
ini_set('display_errors', 'On');

define('string', 'index');

$array = array( 'string' => 'Element with index "string"', 'index' => 'Element with index "index"' );
echo $array[string];
echo '<br>';
echo $array['string'];
echo '<br>';
echo $array['index'];
echo '<br>';
echo $array[index];

[aliento]

nice. thank you !

[namasteji1]

<?php
session_start();session_destroy();
session_start();



if($_POST["regname"] && $_POST["regemail"]
&& $_POST["regmobile"] && $_POST["regpass1"] && $_POST["regpass2"] )

{
if($_POST["regpass1"]==$_POST["regpass2"])
{
$servername="localhost";
    $username="root";
    $conn=  mysql_connect($servername,$username)or die(mysql_error());
    mysql_select_db("test",$conn);
    

$sql = "SELECT `id` from users where `email`= ".$_POST['regemail']."' LIMIT 1";
   $result=mysql_query($sql,$conn) or die(mysql_error());		
$mail_rows = mysql_num_rows($result);
$sql = "SELECT `id` from users where `regname`= '".$_POST['regname']."' LIMIT 1";
   $result=mysql_query($sql,$conn) or die(mysql_error());		
$name_rows = mysql_num_rows($result);
if($mail_rows==0&&$name_rows==0) 
{
$sql="insert into users (name,email,mobile,password)values('$_POST[regname]','$_POST[regemail]','$_POST[regmobile]','$_POST[regpass1]')";
    $result=mysql_query($sql,$conn) or die(mysql_error());		

    print "<h1>you have registered sucessfully</h1>";
   
    print "<a href='index.php'>go to login page</a>";
}
else echo "duplicated data";
}

else print "Passwords doesn't match";
}
else print"Invalid input data";

?>

 

I am getting a sql error, error in where clause for regname and also i would like to know where to put separate echo statements for duplicate username as well as username please?

[namasteji1]

please help anyone?