check if username is allready taken

[benracer]

hi,
whensome registers with my site if their chosen username is the same as another in the database an error is displayed.

$query = "INSERT INTO members (username, password, first, last, email, add1, add2, add3, add4, zip, country, phone)values('$myusername', '$mypassword', '$first', '$last', '$email', '$add1', '$add2', '$add3', '$add4', '$zip', '$country', '$phone')";
mysql_query( $query, $link) or die("The Username/E-Mail Address Entered Is Taken<br>Please go back and choose another" );

how could i make a redirect or a popup to say username is taken?

thanks

[laserlight]

Generally, you might use something like:

if (mysql_query($query, $link))
{
    // Inform user that he/she has been registered
}
else
{
    // Inform user that he/she has chosen a username currently in use.
    // Display form for user to choose another username.
}

Of course, actually checking for the specific error code returned on an attempted unique constraint violation would be better. Otherwise, the user would be told that he/she chose a username already in use if there is some other query related error.

[NogDog]

In MySQL, check for error number 1062. See the [man]mysql_errno/man PHP function.