Checking if a username has been used twice

[frank_solo]

I have written the code for email check, but how and where can I put the code to check if a username has been used twice? Thanks in advance.

<?php

$servername	= "localhost";
$username	= "";
$password	= "";

//validate fields
if(!$_POST["username"] || !$_POST["email"] || !$_POST["password1"] || !$_POST["password2"]){
	echo "<p> </p><p> </p><p> </p><br />Please fill the required fields, <p> </p><p> </p><a href='register.php'>Go to register page</a>";

//validate password
}else if($_POST["password1"] != $_POST["password2"]){
	echo "<p> </p><p> </p><p> </p><br />Please go back, PASSWORDS do not match! <p> </p><p> </p><a href='register.php'>Go to register page</a>";

//validate email	
}else if(!(eregi("^.+@.+\\..+$", $_POST['email']))){	
	echo "<p> </p><p> </p><p> </p><br />Please enter a valid EMAIL! <a href='register.php'><p> </p><p> </p>Go to register page</a>";

//validate captcha
}else if(($_SESSION['security_code'] != $_POST['security_code']) || (empty($_SESSION['security_code'])) ){
	echo "<p> </p><p> </p><p> </p><br />CAPTCHA CODE does not match! <p> </p><p> </p><a href='register.php'>Go to register page</a>";

}else{
	$conn=  mysql_connect($servername,$username,$password)or die(mysql_error());
	mysql_select_db("genesis_members",$conn);

	// check if already registered
	$sql_check = "SELECT * FROM users WHERE email = '".$_POST[email]."'";
	$result_check = mysql_query($sql_check,$conn) or die(mysql_error());		
	$row = mysql_fetch_assoc($result_check);
	if($row['id']){
		echo "<p> </p><p> </p><p> </p><br />EMAIL already registered! <p> </p><p> </p><a href='register.php'>Go to register page</a>";
	}else{

		// insert in db
		$sql = "INSERT INTO users (username, email, password, company, phone, services) VALUES ('".$_POST[username]."', '".$_POST[email]."', '".$_POST[password1]."', '".$_POST[company]."', '".$_POST[phone]."', '".$_POST[services]."')";
		$result = mysql_query($sql,$conn) or die(mysql_error());

		echo "<p> </p><p> </p><p> </p><br /><h1>You Have Successfully Registered</h1>";
		echo "<p> </p><p> </p><br /><a href='main_login.php'>go to login page</a>";
	}
}		

?>

[requinix]

Copy the stuff you did for emails, but replace email-related stuff with username-related stuff.

[frank_solo]

For some reason I was thinking elseif statement. Thank you for the help. Another question how can I limit password to 6 to 8 character?

[Eyewash01]

Use the strlen($string) function to check length of the password

 

http://php.net/manual/en/function.strlen.php