php 关于mongodb的mapreduce的问题

Question

  $mapFunc = <<<EOT
      function() {
        if (!this.summary) {
          return;
        }
        var summary = this.summary;
        if (summary.type || summary.sum) {
        var index = summary.type + '-' + summary.business;
        var data = {
          type: summary.type,
          business: summary.business,
          sum: summary.sum
        };
        emit(index, data);
      }
    }

EOT;

$map = new MongoCode($mapFunc);
$reduceFunc = <<<EOT
  function(k, list) {
    var result = {type:0, business:0, sum: 0};
    for (var b in list) {
    var item = list[b];
      result.type = item.type;
      result.business = item.business;
      result.sum += item.sum;
    }
    return result;
  }

EOT;

$reduce = new MongoCode($reduceFunc);
$params = array(
  "mapreduce" => 'logs',
  "map" => $map,
  "reduce" => $reduce,
  "query" => null,
  "out" => '_ex'
);
$mongo = $this->Log->getDataSource();
$results = $mongo->mapReduce($params);

比如我上面的代码是对logs集合进行统计，还有一个extend_logs集合，字段都是一样的，也需要如上统计方法，用mongodb的mapreduce方法统计数据可以同时对两个表进行相应的操作么？