After mongodb executes the group again, how to fetch a thousand pieces of data and how to limit the operation? The code is as described below?

<code>$keys = array(
    "AREA" => 1
);
$initial = array(
    "show" =>0,
    "click"=>0,
    "cost"=>0,
    
);
$reduce = "function (obj,prev)
    {
        prev.show += obj.show; 
        prev.click += obj.click;
        prev.cost +=obj.cost;
    }
";

$re = $collection->group($keys, $initial, $reduce);</code>

Reply content:

<code>$keys = array(
    "AREA" => 1
);
$initial = array(
    "show" =>0,
    "click"=>0,
    "cost"=>0,
    
);
$reduce = "function (obj,prev)
    {
        prev.show += obj.show; 
        prev.click += obj.click;
        prev.cost +=obj.cost;
    }
";

$re = $collection->group($keys, $initial, $reduce);</code>

aggregation is what you need to use. A lot of information has been covered by searching, so I won’t go into details here. Judging from your code, it should be roughly written like this

<code>db.collection.aggregate([
    {$group: {_id: {AREA: "$AREA"}, show: {$sum: "$show"}, click: {$sum: "$click"}, cost: {$sum: "$cost"}}},
    {$limit: 1000}
]);</code>

The return is a cursor.