Insert Validation

[PaulaRun]

When a new user logs into my site, I add the user id and pswd to my auth table. If the user id is already there, I'd like to display an error rather than the error created by PHP. Is there a graceful way of doing this? I think I probably need to take out the or die from the insert statement and handle the error through mysql_errorno, but how? Do I write a function that looks specifically for the error number?

Thanks in advance for any advice on this!!

$sql = "INSERT INTO auth values ('$userid', password('$password'))"; 
$result = mysql_query($sql) or die ('Error: ' . mysql_error() . '<br>Query: ' . $sql);

[bernouli]

you can make a SELECT query, then num_rows, if sql return rows > 0, it means, the userd is already there, then echo out your own text, if not there, then do INSERT query

[PaulaRun]

A simple solution - Thank you so much!!

[xblue]

SELECT COUNT(*) could be slightly faster even?

apart from that I'd go with what bernouli suggested. there may be other solutions, but this one keeps your code fairly self-explaining while still informing the user properly (meaning: you are able to serve an appropriate error message when the id is already taken, and a different one in your die statement if the update query failed for some unknown reason).

[PaulaRun]

Thanks xblue! I didn't know select count (*) was faster. I'm just learning this stuff!