Add to Value Up to Certain Point

[Octet]

I am creating my purchasing system for my game at the moment, but I am struggling on a part of it and wondered if any of you could offer me some guidance?

The problem I am facing is adding X amount onto a value but if that means it goes over Y then only add up to Y. The player shall purchase a piece of food that shall raise their health by 20 (with 100 being full health), how do I make it so that if the current health value is 90 then it won't go to 110 e.t.c.

So far I have:

 

<?php

session_start();

mysql_connect ("localhost", "root", "") or die ("Couldn't Connect to Server");
mysql_select_db ("Defender_of_Kingdoms") or die ("Couldn't Find Database");

$Purchase = mysql_real_escape_string($_POST['Purchase']);
$Username = $_SESSION['Username'];

$Money = mysql_query ("SELECT * FROM Character_Data WHERE Username = $Username");
while ($Results = mysql_fetch_array($Money))
{

	/* Purchase of Meals */

	if($Purchase = "Peasant")
	{
		if($Results['Silver'] >= 20)
		{
			$Withdraw = $Results['Silver'];
			$Withdraw = $Withdraw - '20';

			$Stamina = $Results['Stamina'];

			/* HELP - ADD TO STAMINA BUT NO FURTHER THAN 100 */

			$Health = $Results['Health'];

			/* HELP - ADD TO HEALTH BUT NO FURTHER THAN 100 */

			mysql_query ("UPDATE Character_Data SET Silver = $Withdraw WHERE Username =$Username");
		}

		die (Header ('Location: ../Errors/Money.php'));
	}

}

?>

 

I hope you understand and that you shall be able to understand me. I don't want the player to be able to gain more than 100% health or stamina through eating.

(I haven't tested the above code so it might spit out some errors)

Thank you

[newttster]

 If $energy + $food <= $full
{
update users energy =energy plus food
}
If $energy + $food >$full
{
update users energy =maxenergy
}

 

Something along those lines.

[Octet]

 If $energy + $food <= $full
{
update users energy =energy plus food
}
If $energy + $food >$full
{
update users energy =maxenergy
}

 

Something along those lines.

Thanks, looks like it should do the job but I haven't tested it yet!

Thanks again, really helpful.