MongoDB MapReduce problem, in codeigniter

Question

我在codeigniter中使用mongodb。

集合

'mtb'
'road'
'minivelo'

php

$map = new MongoCode('
    function(){
        ....
    }
');
$reduce = new MongoCode('
    function(key, values){
                 ....
    }
');
$result = $this->mongo_db->command(array(
    'mapreduce'=>$in, // <= 'mtb' 'road' 'minivelo'
    'map'=>$map,
    'reduce'=>$reduce,
    'query'=>array(...)),
    'out'=>'statistics'
));

我如何从几个集合中获得MapReduce结果?

Answer 1

您只能从具有多个查询的多个集合中获得结果。Mongodb = no join .

看到这个答案:MongoDB映射/减少多个集合?