Check if username already exists ->probl

[Anon]

Before i Insert a news user in the database and run the insert, I would like to check if the username is chosen.

How would this look like?
I guess something like this but I'm not sure

if($username == $uid){
echo "you have to chose another username";
}
else
{
INSERT INTO.....
}

$username is the variable from the form, while $uid is the username I've selected from the database.

[Anon]

Hello,
This is what I did:

$username_check = "SELECT * FROM tablename WHERE username = '$userid'";

$usernameresult = mysql_query($usernamecheck);

$numberrows = mysql_num_rows($usernameresult);

if ($numberrows != "0") {
echo "That username already exsists, please choose another.";
}else{
INSERT INTO....
}

that should work. It worked for me.

[Anon]

Except you must put it in a transaction and lock the table otherwise someone can insert the username between you checking it and inserting it yourself.

Chris