Can't write data into database

[eluser]penta997[/eluser]
Hi. I have a register form. I Have to write data into 3 tables. First table users, 2nd address and 3rd client. When function insert is running i have 2 errors:
A PHP Error was encountered

Severity: 4096

Message: Object of class CI_DB_mysql_result could not be converted to string

Filename: mysql/mysql_driver.php

Line Number: 535

Error Number: 1064

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' 'jakas', 'jakas', '23', '2', '26-315', '2134324')' at line 1

INSERT INTO `address` (`Country_COUNTRY_Id`, `State_STATE_ID`, `USERS_USR_ID`, `ADDR_CityName`, `ADDR_StreetName`, `ADDR_StreetNr`, `ADDR_HomeNr`, `ADDR_ZIP`, `ADDR_Fax`) VALUES ('17', '4', , 'jakas', 'jakas', '23', '2', '26-315', '2134324')

This is my model code

Code:

function create_User()
       {

          

           $USR_ID = $this->db->query("select USR_ID from users where USR_Nick='".$this->input->post('username')."'");
          
        
          
           $ADDR_ID = $this->db->query("select ADDR_ID from address where ADDR_StreetName='".$this->input->post('ulica')."'");
          
          
           $users = array(

               'USR_Nick' => $this->input->post('username'),
               'USR_Pass' => md5($this->input->post('pass')),
               'USR_CreateDate' => date('Y-m-d H:i:s')
           );



           $address = array(
               'Country_COUNTRY_Id' => $this->input->post('country'),
               'State_STATE_ID' => $this->input->post('state'),
               'USERS_USR_ID' => $USR_ID,
               'ADDR_CityName' => $this->input->post('ulica'),
               'ADDR_StreetName' => $this->input->post('ulica'),
               'ADDR_StreetNr' => $this->input->post('nr_ulicy'),
               'ADDR_HomeNr' => $this->input->post('nr_domu'),
               'ADDR_ZIP' => $this->input->post('kod_pocztowy'),
               'ADDR_Fax' => $this->input->post('fax')

           );


           $client = array(
               'Address_ADDR_ID' => $ADDR_ID,
               'CLI_Email' => $this->input->post('email'),
               'CLI_Name' => $this->input->post('imie'),
               'CLI_LastName' => $this->input->post('nazwisko'),
               'CLI_NIP' => $this->input->post('nip'),
               'CLI_Regon' => $this->input->post('regon'),
               'CLI_Pesel' => $this->input->post('pesel'),
               'CLI_Phone' => $this->input->post('telefon')
           );


          
          
           $us = $this->db->insert('users', $users);
            $add = $this->db->insert('address', $address);
           $cli = $this->db->insert('client',$client);
          



           $data = array('us' => $us, 'cli' => $cli, 'add' => $add);

           return $data;

       }