按列数据获取sql查询结果组

Question

我有两张表maintenance_owner，maintenance_users 下面是我的表结构 这是维护用户表 这是维护所有者表现在我可以使用此代码获取所有用户    $this->db->select('mu.*, mo.id_land_owner as mu_owner, mo.group_name, mo.id_mu');    $this->db->from('maintenance_users as mu');    $this->db->join('maintenance_owner as mo','mu.id_maintenance = mo.id_mu');    $this->db->where('mo.id_land_owner', $land_owner_id);    return $this->db->get()->result();它返回[0] => stdClass Object    (        [id_maintenance] => 170        [full_name] =>         [username] => [e-mail]        [password] =>         [token] => 914c001251a1ab018e5eb51923e8f6cc        [mu_owner] => 152        [group_name] => Cleaner        [id_mu] => 170    )[1] => stdClass Object    (        [id_maintenance] => 176        [full_name] =>         [username] => [e-mail]        [password] =>         [token] => 579faa456520656fcc24be047ca6a3bf        [mu_owner] => 152        [group_name] =>         [id_mu] => 176    )[2] => stdClass Object    (        [id_maintenance] => 175        [full_name] =>         [username] => [e-mail]        [password] =>         [token] => d2f6b180a6a7bb32ecd26ffe0297f8f5        [mu_owner] => 152        [group_name] =>         [id_mu] => 175    )但我需要得到这样的结果    [0] => stdClass Object    (        [id] => 30        [id_land_owner] => 152        [group_name] => Cleaner        [group_users] => [e-mail],[e-mail],[e-mail],[e-mail]    )[1] => stdClass Object    (        [id] => 29        [id_land_owner] => 152        [group_name] => Gardener        [group_users] => [e-mail],[e-mail],[e-mail]    )只需要使用 sql 查询来执行此操作我正在使用 codeigniter fraework