CODEWITHSUNDEEP
phpmysqlmongodb
hao
hao

Reputation: 655

Using Group in MongoDB

I have a collection "crawl_data" in my DB name "nutch". In crawl_data, I have a field called "Domain". Now I want to count the number of rows that are under the same Domain name with PHP.

The MYSQL equivalent would be:

 SELECT DOMAIN, COUNT(*) AS NUMOFURLS FROM Crawl_data GROUP BY DOMAIN

I tried the code :

$keys = array("Domain" => 1);
$inital = array("count" => 0);
$reduce = "function (obj, prev) { prev.count++; }";
$cursor = $collection->group($keys,$inital,$reduce);
foreach($cursor as $doc){
  echo var_dump($doc);
}

The output is :

  array(3) { [0]=> array(2) { ["Domain"]=> string(13) "Straits Times"      ["count"]=> float(5127) } 

  [1]=> array(2) { ["Domain"]=> string(7) "Reuters" ["count"]=> float(3201) } 

  [2]=> array(2) { ["Domain"]=> string(17) "Channel News Asia" ["count"]=> float(2812) } } float(11140) int(3) float(1)

print_r($curosr) gives:

 Array ( [retval] => Array ( [0] => Array ( [Domain] => Straits Times   [count] => 5127 ) 
 [1] => Array ( [Domain] => Reuters [count] => 3201 ) 
 [2] => Array ( [Domain] => Channel News Asia [count] => 2812 ) ) [count] => 11140 [keys] => 3 [ok] => 1 ) 1

How should I output the $doc variable to echo only the domain name and the count number

For example: Domain :Straits Times; number : 5127

Upvotes: 0

Views: 44

Answers (2)

Sammaye
Sammaye

Reputation: 43884

You shouldn't be using the PHP group function ( http://php.net/manual/en/mongocollection.group.php ) on the MongoCollection to do this.

That is a very old and out dated method of grouping.

Now-a-days you use the aggregation framework ( http://php.net/manual/en/mongocollection.aggregate.php and http://docs.mongodb.org/manual/core/aggregation-introduction/ ):

$result = $db->collectionp->aggregate([
    ['$group' => ['_id' => '$Domain', 'count' => ['$sum' => 1]]]
]);

foreach($result['result'] as $doc){
    echo 'Domain: ' . $doc['_id'] . ' with count: ' . $doc['count'];
}

Upvotes: 1

Raj
Raj

Reputation: 150

foreach($cursor['retval'] as  $doc){

 $test .= $doc["Domain"] ." ".$doc["count"]."<br>";

}

echo $test;

Upvotes: 1

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