While loop isn't adding a number to my variable...

<?php
require_once('db_con.php');
$ind_inv_result = mysql_query("SELECT DISTINCT `desc`,`cat_no` FROM `inventory` WHERE `po_num` = '6000'");
while ($ind_inv_row = mysql_fetch_array($ind_inv_result)){
	if($main_item){
		echo 'main set';
		$main_item++;
	}
	if(!$main_item){
		echo 'main not set';
		$main_item=0;
	};
	echo $main_item;
}?>
	

PHP:

That is my code. There are 4 results from the query, so it should run the while loop 4 times. The first time it goes through, it should output:

main not set0

then the next 3 times it should output
main set1-3

correct? It is outputting mainnotset0 4 times and I don't understand why... any help is greatly appreciated!

 

if(!isset($main_item))

as

if(!$main_item) is also true for 0 value.

 

sorry got that the other way around

if(isset($main_item))

as

if($main_item) is also FALSE for 0 value.

 

Great!! Thanks so much for your help!!