Update or add?

I have a table where I want to update each record with today's date as it's hit, or add the record if it's not in there: +------+-----------------+------------+ | id | creation_date | last_hit | +------+-----------------+------------+ I'm trying to do this with a minimum of hits to the db, so rather than first searching to see if a matching record is in there, I thought I'd just go ahead and update the matching record, check to see if it failed, and if it failed then add a new one, like this: $id = $_GET['id']; // Update $query = "update table set last_hit=NOW() where id='$id'"; $result = mysql_query($query); // Add if(the update failed) { $query = "insert into table (id,creation_date,last_hit) values ('$id',NOW(),NOW())"; $result = mysql_query($query); } What's the fastest way to check if the update failed?