试图显示我们在数据库中有多少行

Question

I have a database of airfield cards and would like to show how many of them we have, on the first page of the site. I have looked into it, and found this on the web, but when I add it to my site, I get the dreaded blank screen error, so there's obviously something not right in the code.

I am simply trying to return (how many) cards there are in the database, then display it as a number to the user. Like this...

Card number = 380

$result = mysql_query("SELECT COUNT(*) AS `count` FROM `users` WHERE 
visible='0'");
$row = mysql_fetch_assoc($result);
$count = $row['count'];