tablesort,page,join的联合使用

$query = db_select('og_membership', 'om')->extend('PagerDefault')->extend('TableSort');
    $query->leftjoin('og_users_roles', 'ou', 'om.gid = ou.gid AND om.etid=ou.uid');
    $query->leftjoin('og_experience_total', 'ot', 'om.gid = ot.gid AND om.etid=ot.uid');
    $query->fields('om',array('etid','created','id'));
    $query->addField('ou', 'rid', 'ou_rid');
    $query->addField('ot', 'rid', 'ot_rid');
    $query->condition('om.entity_type','user')
    ->condition('om.gid',$gid)
    ->limit(10)
    ->orderBy('ou.rid', 'DESC')
    ->orderByHeader($header)
    ->orderBy('om.created', 'DESC');
    $result = $query->execute()->fetchAll();
    $role =  array(3=>'管理员');
   
    $options = array();
    foreach ($result as $value) {
        $userinfo = user_load(intval($value->etid));
        //角色ID
        $str  = empty($value->ou_rid)?'':'【'.$role[$value->ou_rid].'】';
        $rank_id = empty($value->ot_rid)?1:$value->ot_rid;
        $options[$value->id] = array(
                'nickname' => $str.$userinfo->name,
                'rank' => $rank[$rank_id],
                'joined' => date('Y/m/d',$value->created),
        );
    }
    $form['member_list'] = array(
            '#type' => 'tableselect',
            '#header' => $header,
            '#options' => $options,
            '#empty' => t('暂时没有记录.'),
    );
    $form['buttons'] = array();
    $form['buttons']['submit'] = array(
            '#type' => 'submit',
            '#value' => t('移出小组'),
            '#submit' => array('remove_member_submit'),
    );
    $form['pager'] = array('#markup' => theme('pager'));
    return $form;