PHP & MySQL for a registration page?

[MtPHP]

Hi I'm making a page, register.php for my site, almost there!
I am trying to make it so only one person can have a username say if someone has the username 'User444' someone else can't have that username. How?
Basically how do I search a MySQL table for 'this' and if 'this' exists do 'this' else do 'this'

[nnichols]

You should use two methods to safe-guard against duplicate usernames -

First - the username column of your db should have a UNIQUE KEY on it.

Second - check for the existance of the new username

$sql = "SELECT * FROM tbl_name WHERE username='$username'";
$result = mysql_query($sql);
if ($result) {echo 'Some error msg';}
else {/*insert code goes here*/}

Hope this helps 😉

[MtPHP]

YO!
Worked!
Thankies!