'replace' with 'where'

hello php-db people. i'm wondering if you could set me straight here. here's my code snippet: $result_insert = mysql_query("replace into wantlist where id = '$id' values ('', '$artist', '$title', '$tracks', '', '', '')"); the $id is already defined in the url, by the way (ex. bla.com/page.php?id=3). i'm wondering if the 'where' syntax works with replace because i need to essentially edit a record via the web. i've checked on the mysql.com manual and it doesn't specify this (or at least i couldn't find it). thanks again, Matt