List online users and get total "talep" count each user - php

Question

I have a table for Talepler and Yonetim. Now Each talepler has his own users. and each user is mapped to that talepler by a field called user id. So how i can print out online users with total count in Talepler table by Count(*) with Join query.
Here my code with helper function. But i want with join.
$this->db->select('yonetim.id, yonetim.user, yonetim.onoff');
$this->db->from('yonetim');
$this->db->where('yonetim.onoff',1);
$query = $this->db->get();
$datam = array();
foreach ($query->result() as $data) {
$count = checkIfuserMax($data->id);
if($talepsay < 10 ) {
$datam[] = array(
'id' => $data->id,
'user' => $data->user,
'onoff' => $data->onoff,
'toplamtalep' => $count
);
}
}
echo json_encode($datam);
and here my helper function
function checkIfuserMax($id) {
$ci =& get_instance();
$ci->db->select('COUNT(*) as toplam');
$ci->db->where(array( 'hangiadmin' => $id, 'onaylayan' => null));
$ci->db->from('talepler');
$query = $ci->db->get();
$result = $query->result();
return $result[0]->toplam;
}
Finally here my json result
[
{
"id": "1",
"user": "user1",
"onoff": "1",
"toplamtalep": "13"
},
{
"id": "2",
"user": "user2",
"onoff": "1",
"toplamtalep": "0"
},
{
"id": "4",
"user": "user3",
"onoff": "1",
"toplamtalep": "2"
},
{
"id": "173",
"user": "user4",
"onoff": "1",
"toplamtalep": "6"
}
]
This code working properly. But i want to make this same result with "JOIN" query. Could you please help me about this query?