ThinkPHP's method of implementing multi-table query and paging functions

// 异步请求试卷夹下某一个试卷夹的列表
public function ajaxLists() {
  extract($_GET);
  $page = intval($_GET['p']);
  $prefix = C('DB_PREFIX');
  $collect = $prefix . 'collect';
  $resource = $prefix . 'resource';
  if ($keyword) {
    $arr = preg_split('/ /', $keyword);
    // 搜索标签
    foreach ($arr as $value) {
      $id = A('Home/Papers')->trunWordToId(array($value));
      if ($id) {
        $where['resource.rta_id'][] = array('LIKE', '%,' . $id . ',%');
      }
      $where['resource.re_title'][] = array('LIKE', '%' . $value . '%');
    }
    if ($where['resource.rta_id']) {
      $where['resource.rta_id'][] = 'AND';
    }
    if ($where['resource.re_title']) {
      $where['resource.re_title'][] = 'OR';
    }
    if ($where['resource.re_title'] && $where['resource.rta_id']) {
      $where['_logic'] = 'OR';
    }
  }
  if ($where) {
    $map['_complex'] = $where;
  }
  $map['collect.a_id'] = $this->authInfo['a_id'];
  $map['_string'] = 'collect.col_object_id = resource.re_id';
  // 总数
  $count = M()->table("$collect collect, $resource resource")->where($map)->count();
  // 总页数
  $regNum = ceil($count/6);
  // 验证当前请求页码是否大于总页数
  $page = $page > $regNum ? $regNum : $page;
  // 引入ajax分页库
  import("@.ORG.Util.AjaxPage");
  $Page = new AjaxPage($count, 6);
  $list['page'] = trim($Page->show());
  $list['list'] = M()->table("$collect collect, $resource resource")->where($map)->order('col_id DESC')->limit($Page->firstRow . ',' . $Page->listRows)->field('collect.col_id,collect.col_object_id,resource.re_id,resource.re_title,resource.re_created,resource.re_collect_count,resource.re_score_count,resource.re_score_num,resource.rta_id')->select();
  // 获取试卷的标签
  $wheree['rta_id'] = array('IN', trim(str_replace(',,', ',', implode('', getValueByField($list['list'], 'rta_id'))), ','));
  $tag = setArrayByField(M('ResourceTag')->where($wheree)->field('rta_id,rta_title')->select(), 'rta_id');
  // 把标签和试卷对应
  foreach ($list['list'] as $key => &$value) {
    $str = '';
    foreach ($tag as $k => $v) {
      if (strpos($value['rta_id'], ',' . $k . ',') !== FALSE) {
        $str .= ' | ' . $v['rta_title'];
      }
      $value['rta_title'] = trim($str, ' |');
    }
    if ($keyword) {
      foreach ($arr as $vv) {
        if (strpos($value['re_title'], $vv) !== FALSE) {
          $value[&#39;re_title&#39;] = str_replace($vv, &#39;<font color=\&#39;red\&#39;>&#39; . $vv . &#39;</font>&#39;, $value[&#39;re_title&#39;]);
        }
        if (strpos($value[&#39;rta_title&#39;], $vv) !== FALSE) {
          $value[&#39;rta_title&#39;] = str_replace($vv, &#39;<font color=\&#39;red\&#39;>&#39; . $vv . &#39;</font>&#39;, $value[&#39;rta_title&#39;]);
        }
      }
    }
    $value[&#39;re_created&#39;] = date(&#39;Y-m-d&#39;, $value[&#39;re_created&#39;]);
  }
  echo json_encode($list);
}