[PHP][MySQL]mysql_num_rows- zły argument Opcje

[Testosteron]

[PHP] pobierz, plaintext 
<?php
session_start();
include("function.inc");
include("lang/polish.inc");
 
If (empty($_POST['nick']) || empty($_POST['pass']) )
{
?>
<form method="POST" action="loguj.php">
	<input type="text" name="nick">
	<input type="password" name="pass">
	<input type="submit" value="Loguj">
</form>
<?php
}
else
{
	connect();
	$nick = mysql_escape_string($_POST['nick']);
	$pass = mysql_escape_string($_POST['pass']);
	$pass = koduj ($pass);
 
	$zapytanie = mysql_query("SELECT 'nick' FROM 'users' WHERE nick = '$nick' AND pass = '$pass'");
	echo mysql_num_rows($zapytanie);
 
}
 
?>
[PHP] pobierz, plaintext 

Wyrzuca mi następujący błąd
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in c:\usr\apache\httpd\html\anonse\include\loguj.php on line 19

Z czym to jest związane?