http://samueleresca.net/2014/06/introduzione-mongodb/

dbProvide.php

<?php
$host = 'localhost:27017';
$dbname = 'myMongoDb';
$colname = "emp";

try {
    //Istanzio la connessione all host
    $conn= new MongoClient($host);
    //Seleziono il database tramite il $dbname
    $db=$conn->selectDB($dbname);
    //Seleziono la connection tramite il $colname
    $coll=$conn->selectCollection($dbname,$colname);
    //Effettuo le query di ricerca dei valori
    //Cerco le row con la field deptno = 20
    $cursor=$coll->find(array("deptno"=>20));
    $cursor->sort(array("sal"=>1));
    foreach ($cursor as $c){
        foreach ($c as $key=>$val){
           if($key != "_id"){
                      print "$val t";
                    }
        }
        print "n";
    }
} catch (Exception $e) {
    print "exception: n";
    die($e->getMessage()."n");
}