<?php 

$loginSelect = "SELECT COUNT(id) AS nbLogin FROM users WHERE login = %s";

      $loginQuery = sprintf($loginSelect, $this->input->post('login'));

      $loginResult = $this->db->query($loginQuery);

      $nbLogin = $loginResult->result_array();

      if($nbLogin['nbLogin'] > 0){



        $this->validation->login_error = $this->lang->line('This login is already used.');

        $this->layout->view('profile/inscriptionForm');

        return FALSE;

      }



      $emailSelect = "SELECT COUNT(id) AS nbEmail FROM users WHERE email = %s";

      $emailQuery = sprintf($emailSelect, $this->input->post('email'));

      $emailResult = $this->db->query($emailQuery);

      $nbEmail = $emailResult->result_array();

      if($nbEmail['nbEmail'] > 0){



        $this->validation->email_error = $this->lang->line('This email is already used.');

        $this->layout->view('profile/inscriptionForm');

        return FALSE;

      }



      $nameSelect = "SELECT COUNT(id) AS nbName FROM users WHERE lastname = %s AND firstname = %s";

      $nameQuery = sprintf($nameQuery, $this->input->post('lastname'), $this->input->post('firstname'));

      $nameResult = $this->db->query($nameQuery);

      $nbName = $nameResult->result_array();

      if($nbName['nbName'] > 0){



        $this->validation->firstname_error = $this->lang->line('These firstname and lastname are already used.');

        $this->layout->view('profile/inscriptionForm');

        return FALSE;

      } 

<?php 

$selectQuery = "SELECT login, email, firsname, lastname FROM users" .

          "WHERE login = %s OR email = %s OR (firstname = %s AND lastname = %s);";

      $selectQuery = sprintf(

        $selectQuery,

        $this->input->post('login'),

        $this->input->post('email'),

        $this->input->post('firstname'),

        $this->input->post('lastname')

      );

      $selectResult = $this->db->query($selectQuery);

      $selectArray = $selectResult->result_array();

      if($selectArray['login'] == $this->input->post('login')){



        $this->validation->login_error = $this->lang->line('This login is already used.');

        $this->layout->view('profile/inscriptionForm');

        return FALSE;

      }elseif($selectArray['email'] == $this->input->post('email')){



        $this->validation->email_error = $this->lang->line('This email is already used.');

        $this->layout->view('profile/inscriptionForm');

        return FALSE;

      }elseif($selectArray['firstname'] == $this->input->post('firstname')

        AND $selectArray['lastname'] == $this->input->post('lastname')){



        $this->validation->firstname_error = $this->lang->line('These firstname and lastname are already used.');

        $this->layout->view('profile/inscriptionForm');

        return FALSE;

      } 

<?php 

$result = array(

     array(

           'login' => 'toto',

           'pass' => 'tata'

     ),

     array(

           'login' => 'titi',

           'pass' => 'tutu'

     )

)