like for mysql?
make a table called downloads and the table would just be "int" call it dlnum, insert 1 row
the php would be as follows
<?
//adds download to database
$conn = mysql_connect("localhost", "username", "password");
mysql_select_db("database");
$query = "SELECT dlnum FROM downloads";
$result = mysql_query($query) or die(mysql_error());
$row = mysql_fetch_object($result);
$dlnum = $row->dlnum;
$dlnum = $dlnum + "1";
$query = "UPDATE downloads SET dlnum = '$dlnum' WHERE id = '1'";
mysql_query($query);
mysql_close($conn);
?>
to view how many downloads there have been do the following.
<?
$conn = mysql_connect("localhost", "username", "passwords");
mysql_select_db("database");
$query = "select * from downloads";
$result = mysql_query($query) or die(mysql_error());
$row = mysql_fetch_object($result);
$dlnum = $row->dlnum;
echo "Downloads of something: ".$dlnum;
mysql_close($conn);
?>