How do I put extra number at the end of username if duplicate

Question

Hard to explain, and let me show an example.

1. If username foo already exists in MySQL I want php script will allow it but to be foo1

Answer 1

I would use something like this:

// the username
$username = "foo";

// find all users like foo%
$q = mysql_query("SELECT * FROM users WHERE username LIKE '".$username."%' ORDER BY id DESC");

// no users
if (mysql_num_rows($q) == 0) {
    // create $username
}
else {

    $last_num = 0;

    // find all foo users
    while ($row = mysql_fetch_array($q)) {

        // match foo + number
        if (preg_match("/^".preg_quote($username)."+([0-9]+)$/i", $row['username'], $match)) {

            // extract the number part
            $num = (int) $match[1];

            // set the highest number
            if ($num > $last_num) $last_num = $num;
        }
    }

    // append the highest number to the username
    if ($last_num > 0) $username .= $last_num + 1;

    // create $username
}