Getting error in mysql_num_rows()

[Bharati Raul]

Hi,

I am facing problem in mysql_num_rows() function.

Following is the code :

$query="SELECT * FROM tbl_name where email='$email'";
$result=mysql_query($query);
$num=mysql_num_rows($result);

This code is working fine when I am testing in a single file,
but when I am including this file in some other file, then I am getting error following error.

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /web/development/usr/local/etc/httpd/htdocs/... on line 45

Give me the solution...