Building unread_message counter ends in resource id error - php

Question

Trying to get the unread messages from my database with this function, but I end in resource id errors like this one: "Resource id #45"
function unread_message_count() {
$sql = "SELECT conversations_messages.message_id, conversations_members.user_id, conversations_members.conversation_last_view, conversations_messages.message_date
FROM conversations_members
INNER JOIN conversations_messages ON conversations_messages.user_id = conversations_members.user_id
WHERE conversations_members.conversation_last_view < conversations_messages.message_date AND conversations_members.user_id = {$_SESSION['user_id']}";
$result = mysql_query($sql);
return $result;
}
I call the function this way, but to nothing prints:
$count = unread_message_count();
echo $count;

Answer 1

mysql_query() returns a resource on success, or FALSE on error, you need to fetch the data from results, like:
...
$result = mysql_query($sql);
$rows = mysql_fetch_array($result);
return $rows;
Btw, mysql_ is deprecated, MySQLi or PDO_MySQL extension should be used.

Answer 2

mysql_query() returns a resource. The to string (implicitly triggered by using echo to output it) of that is Resource ID # followed by the id.
A resource in PHP is only supposed to be used with other PHP functions. This includes but is not limited to file, curl, ftp handles, etc.
use mysql_fetch_array() (or similar)
Just Try this
function unread_message_count() {
$sql = "SELECT conversations_messages.message_id, conversations_members.user_id, conversations_members.conversation_last_view, conversations_messages.message_date
FROM conversations_members
INNER JOIN conversations_messages ON conversations_messages.user_id = conversations_members.user_id
WHERE conversations_members.conversation_last_view < conversations_messages.message_date AND conversations_members.user_id = {$_SESSION['user_id']}";
$result = mysql_query($sql);
$data = mysql_num_rows($result);
return $data;
}