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View Full Version : Check for Unique Username



Jon W
01-06-2008, 06:37 AM
The title say it all. How can I create a script that will check and see in my database to see if there is already a unique Username. I'm doing this for a Register page.

Thanks for you help in advance.

Jacobb123
01-06-2008, 06:53 AM
Depending on how your database is setup you would want to create a form and the mysql query would look something like this


$sql=mysql_query("SELECT user_name FROM your_table_here WHERE username='{$_POST['userid']}'");
$num_rows=mysql_num_rows($sql);

if($num_rows >1){

echo 'User Id already exists';
}


here is a tutorial about forms. http://www.tizag.com/phpT/forms.php

It should help you out with the basics of this.

kbluhm
01-06-2008, 05:17 PM
You'll not want to check for $num_rows > 1... this will only return TRUE if the user name exists twice or more in the database. That code will allow a name to be registered twice before disallowing it to be registered again.

All you really need to check is if any rows were returned, since 0 is equivalent to FALSE and everything above equates to TRUE:


$qry = sprintf( 'SELECT `id` FROM `users` WHERE `userName` = \'%s\'', mysql_real_escape_string( $_POST['userName'] ) );
$res = mysql_query( $sql );
$num = mysql_num_rows( $res );

if ( $num )
{
echo 'This user already exists';
}



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