Why mysqli_num_rows always returns NULL? - php

Question

I want to count the rows in the users table with specific name and pwd which should be 1 if existed.
but the result always return null(not 0),no matter whether the user existed or not.
I even change the query simple to "SELECT * FROM users", and it ended with the same result.
And I am pretty sure that the name of the DATABASE and TABLE are true,and the table is not empty!
By the way,why I have to use "#" symbol before "mysqli_query" in order to get rid of error?
thx!
enter code here
<?php
#$mysql_db_hostname = "localhost";
$mysql_db_hostname = "127.0.0.1";
$mysql_db_user = "root";
$mysql_db_password = "";
$mysql_db_database = "smartFSUsers";
$con = mysqli_connect($mysql_db_hostname, $mysql_db_user, $mysql_db_password,$mysql_db_database);
if (!$con) {
trigger_error('Could not connect to MySQL: ' . mysqli_connect_error());
}
$name = $_GET["name"];
$password = $_GET["password"];
$query = "SELECT * FROM users WHERE name='$name' AND password='$password'";
$result =#mysqli_query($query,$con);
echo($result);
$row=#mysqli_num_rows($result);
echo"the row num is $row \n";
?>

Answer 1

RTM: http://php.net/mysqli_query
$result =#mysqli_query($query,$con);
You've got your parameters reversed. $con MUST come first:
$result = mysqli_query($con, $query) or die(mysqli_error());
If you had bothered adding error correction to your code, you'd have been told about this. But nope, you opted for # to hide all those error messages.