Mongo distinct sort query using PHP driver - php

Question

Having some trouble issuing a simple query from the PHP Mongo driver.
This is the shell query:
db.testing.distinct('summary.type').sort();
According to the documentation, I can do a db->command to use the distinct query. Here is what I've tried:
$all_types = $db->command(
array(
"distinct" => "summary.type",
"key" => "summary.type"
)
);
var_dump($all_types);
But rather than getting back the data I expect, I only get a cursor with indexes like stats, nscanned and nscannedObjects
What am I doing wrong?
Thanks,
ns

Answer 1

Commands don't return a MongoCursor object, but always just one document. Just like with findOne(). In this returned document, the values array element in the returned array contains an array of all your results:
<?php
$m = new Mongo; $c = $m->demo->pubs; $c->drop();
$c->insert( array( 'name' => 'Betsy Smith', 'city' => 'London' ) );
$c->insert( array( 'name' => 'London Tavern', 'city' => 'London' ) );
$c->insert( array( 'name' => 'Lammars', 'city' => 'Manchester' ) );
$c->insert( array( 'name' => 'Weatherspoons', 'city' => 'Coventry' ) );
$r = $m->demo->command( array(
'distinct' => 'pubs',
'key' => 'city',
'query' => array( 'name' => array( '$ne' => 'Weatherspoons' ) )
) );
var_dump( $r['values'] );
?>
Which returns:
array(2) {
[0] =>
string(6) "London"
[1] =>
string(10) "Manchester"
}

Answer 2

The result you're looking for is actually in the values key of the command's response. If you look at the entire output of var_dump(), you'll see keys for values, stats (which you referred to), and ok.
On the JavaScript console, the collection's distinct() helper function actually handles the unwrapping for you, which you can see when viewing the source:
> db.testing.distinct
function (keyString, query) {
var res = this._distinct(keyString, query);
if (!res.ok) {
throw "distinct failed: " + tojson(res);
}
return res.values;
}
Also, I believe you have an error in the command being issued through the PHP driver. The distinct option should refer to the collection name, and key should refer to the field name. See the Distinct docs for more information on that.