Question: ```
function get_result_professions($key_word)  
{  
    $sql = "SELECT users.name FROM users 
            inner join users_has_professions  on users_has_professions.users_id  = users.id 
            inner join professions on users_has_professions.professions_id  = professions.id  
            where professions.key_word = ?  ";

    return   $this->db->get()->query($sql, $key_word);
} 

```

When I execute this code I receive the following error:

```
A Database Error Occurred

Error Number: 1096

No tables used

SELECT *

Filename: /var/www/expertt/models/search_model.php

Line Number: 31

```

How can I solve this problem? Thanks in advance.

Answer: 
Hangouts does not currently have a public API.

That said, messages delivered to the Google Talk XMPP server (talk.google.com:5222) are still being delivered to users via Hangouts. This support is only extended to one-on-one conversations, so the notification can't be delivered to a group of users. The messages will need to be supplied through an authenticated Google account in order to be delivered.
I send alarms and other notifications with a python script (failures on database server, partitions without free space, etc), using hangouts. It's easy. Look at <http://www.administracion-linux.com/2014/07/enviar-mensajes-por-hangout-desde.html> to send hangouts.