Top PM's sent by a member

[Johnnnnny1986]

im trying to get a top pm's sent member list ive got the total pms sent working and the top list working but i cant get the MySQL database to update the number of pms sent my that member ive tried lots of ways and it just gets the total up to 1 can someone help me with the coding for this bit please.

I thought this would do it but it dosent

$sqlthing = mysql_query("SELECT * FROM pmssent WHERE '$username'");
$pmssent=(mysql_result($sqlthing,0,"pmssent"));
$pmssent=$pmssent+1;

$query = "update members set pmssent='$pmssent' where username='$username'";
mysql_query($query);