PHP SQL更新语句

<?php

if ($wid!=""){  //确认工资条没有问题

$y_title="1";

$sql= "update wage set Signature='$y_title' where
wid='$wid'";

mysql_query($sql) or die(mysql_error());

echo("<script type='text/javascript'>
alert('确认成功！');location.href='view_wage.php';</script>");

mysql_close();

}

?>