PHP 5.3.10的奇怪的减法问题

Question

I have a very strange issue with PHP.

I run this very simple code:

include("db_credentials.php");
//
$conn = mysql_connect($host, $user, $pass);
$sel = mysql_select_db($db, $conn);
  //
  $result = mysql_query("SELECT * FROM tokens");
  $res = mysql_num_rows($result);
  //
echo (50000-$res);

but the final subtraction result is NEVER right. I tried echo gettype($res) and $res is an integer (what else could it be?), but I have no idea of what could cause this. Is it a PHP bug? Is there something wrong with my code?

Answer 1

I'm pretty sure I've run into this before but can't remember exactly where or how.

This isn't an answer per say, but rather a suggestion.

Try this code instead

include("db_credentials.php");
$conn = mysql_connect($host, $user, $pass);
$sel = mysql_select_db($db, $conn);

$result = mysql_query("SELECT COUNT(*) as count FROM tokens");
$row = mysql_fetch_assoc($result);
$res = $row['count'];

echo (50000-$res);