SQL更新说成功，但不更新数据库中的表

Question

I'm having an issue with a SQL update query, it says successful but doesn't actually update the database record.

<?php

    require_once('auth.php');

    $host="localhost"; // Host name 
    $username="root"; // Mysql username
    $password="sysadmin"; // Mysql password 
    $db_name="Elite"; // Database name 
    $tbl_name="Triage"; // Table name 

    mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
    mysql_select_db("$db_name")or die("cannot select DB");

    $sql="UPDATE Triage SET directly='$directly', psychologically='$psychologically' WHERE Reference='$Reference'";
    $result=mysql_query($sql);

Answer 1

$sql="UPDATE Triage SET directly='$directly', psychologically='$psychologically' WHERE Reference='$Reference'";

none of the variables used in that query have been defined in the code above. $directly,$psychologically,$Reference : none have a value. Define values for those and that's it.

That $Reference is a must, even If others aren't.

Answer 2

$refrence="1";
$sql="UPDATE Triage SET directly='$directly' AND psychologically='$psychologically' WHERE Reference='$Reference'";

replace $refrence with your MySQL ref

Answer 3

Use this syntax

 $sql=  UPDATE Triage SET directly=?, psychologically=? WHERE Reference=?";
 $param->execute(array($directly,$psychologically,$Reference));
 $result=mysql_query($param);