Recover Codeigniter database value - Mysql

Question

In a user form, I upload information such as username, password and permissions.

But now I’ve included it in the permissoes a field called grupo.

And I included it in the usuarios this field, so that; every time the user’s permission is chosen, the group field loads the group name of the selected permission group.

I know that in MYSQL, the querie used is

`SELECT `grupo` FROM `permissoes` WHERE `id` = 1`.

But I couldn’t do it in the codeigniter.

In the edit function,

I retrieve user data and display the information in the view as follows:

User Controller

//Obtem dados do usuário
$this->data['usuarios']   = $this->Usuarios_model->obter_id($this->uri->segment(4));
//Obtem Permissões Ativas
$this->data['permissoes'] = $this->Permissoes_model->obter_ativo('permissoes', 'permissoes.id,permissoes.nome');
//Carrega View
$this->template->admin_render('admin/usuarios/editar', $this->data);

Model User:

//Função obter ID
function obter_id($id){
    $this->db->select('usuarios.*, permissoes.nome as permissao');
    $this->db->select('usuarios.*, permissoes.grupo as grupo');
    $this->db->join('permissoes', 'usuarios.permissoes_id = permissoes.id', 'left');
    $this->db->where('usuarios.id',$id);
    $this->db->limit(1);
    return $this->db->get('usuarios')->row();
}

Model Permissions

//Exibir somente permissões ativas
function obter_ativo($tabela,$campos){        
    $this->db->select($campos);
    $this->db->from($tabela);
    $this->db->where('situacao',1);
    $query = $this->db->get();
    return $query->result();;
}

View User

//View do formulário usuário
<select name="permissoes_id" id="permissoes_id" class="form-control">
   <?php foreach ($permissoes as $permissao) {
      if($permissao->id == $usuarios->permissoes_id){ $selected = 'selected';}else{$selected = '';}
     echo '<option value="'.$permissao->id.'"'.$selected.'>'.$permissao->nome.'</option>';
   } ?>
</select>
<label>Grupo</label>
<input "Aqui vai o nome do grupo referente a permissão selecionada" />

User tables

`id` INT(11) NOT NULL AUTO_INCREMENT,
`primeiro_nome` VARCHAR(40) NOT NULL,
`ultimo_nome` VARCHAR(40) NOT NULL,
`nome_usuario` VARCHAR(40) NOT NULL,
`telefone` VARCHAR(20) NULL DEFAULT NULL,
`email` VARCHAR(80) NOT NULL,
`senha` VARCHAR(45) NOT NULL,
`permissoes_id` INT NOT NULL,
`grupo` INT NOT NULL,

Tables Permissions

`id` INT(11) NOT NULL AUTO_INCREMENT,
`nome` VARCHAR(80) NOT NULL,
`descricao` VARCHAR(80) NULL DEFAULT NULL,
`grupo` INT NOT NULL,
`permissoes` TEXT NULL,
`situacao` TINYINT(1) NULL,