UPDATE addingValueToExisting SET GameScore = GameScore+10 WHERE Id = 4;
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
mysql_query("UPDATE `some_table` SET `value` = `value` + 1000 WHERE `id` = 1");
mysql_close($con);
?>