MongoDB文档中的多个值可以使用PHP分别返回吗？

Question

Using MongoDB with PHP driver;

For the purpose of the question, I have a simple Mongo collection and each doc has 4 rows. I'd like to get the distinct username AND id when doing a query, while using a where clause based on the public value.

my code for testing:

$m  = new Mongo;
$db = $m->selectDB("test");
$db->dropCollection("activities");
$collection = $db->activities;

$collection->insert(array("username" => "brady", "public" => "Y", "userId" => "1", "activity" => "blah"));
$collection->insert(array("username" => "scott", "public" => "Y", "userId" => "2", "activity" => "blah"));
$collection->insert(array("username" => "brady", "public" => "N", "userId" => "1", "activity" => "blah"));

$cursor = $db->command(array("distinct"=> "activities", "key" => "username", "query"=>array("public"=>"Y")));

var_dump($cursor['values']);

The dump produces:

array(2) { [0]=> string(5) "brady" [1]=> string(5) "scott" }

I want the username, but I also want the userId. Could anyone help me figure out how to get both values from the doc while using distinct?

Answer 1

You can't do this with distinct: http://docs.mongodb.org/manual/reference/command/distinct/ it only supports single keys.

You can however achieve this with the aggregation framework. It should be easy to translate this to PHP:

db.activities.aggregate({ $match: { public: "Y" } },
    {
      $group: {
        _id: 1,
        names: { $addToSet: "$username" },
        ids: { $addToSet: "$userId" }
      }
    }
});

On your test data I get:

{
    "result" : [
        {
            "_id" : 1,
            "names" : [
                "scott",
                "brady"
            ],
            "ids" : [
                2,
                1
            ]
        }
    ],
    "ok" : 1
}