{mapreduce:"topic",
query:{'time':{'$gte':1443715200}},
map:function(){emit({name:this.name},this.clickNum);},
reduce:function(clickNum,numbers){return Array.sum(numbers);},
out:{inline:1}});
用上面的程式碼查詢後一共有300條數據,這個時候如何對集合進行分頁,例如一頁20條