Question

Trying to do a simple mongodb query that drives me mad…. I have the following table/db:

[_id] => MongoId Object (
    [$id] => 4f22efa1ef9dec8495b374bc
)
[h1] => a
[h2] => b
[h3] => c

[_id] => MongoId Object (
    [$id] => 4f22efa1ef9dec8495b374bd
)
[h1] => d
[h2] => e
[h3] => f

Using the mongo tool command line and typing:

db.things.find({$or: [{'h1' : 'a'},{'h1': 'd'}]})

I get:

{ "_id" : ObjectId("4f22efa1ef9dec8495b374bc"), "h1" : "a", "h2" : "b", "h3" : "c" }
{ "_id" : ObjectId("4f22efa1ef9dec8495b374bd"), "h1" : "d", "h2" : "e", "h3" : "f" }

Which is fine. However trying doing the same from PHP, I get nothing ??:

$m = new Mongo();
$db = $m->selectDB('testdb');
$collection = new MongoCollection($db, 'things');
$query = array( '$or' => array( array('h1' => 'a')), 
                                array('h1' => 'd'));
$cursor = $collection->find($query);

I do not see what I am doing wrong, but I have tried anything (or I think so) for 3 days now and it will not work. If I do queries using ‘>=’ ‘<=’ ‘<>’ ‘<‘ ‘>’ it works fine but using ‘=’ as in this case it does not.

Thanks for your effort !

Answer 1

You’re better off using $in for your given example, i.e.:

$collection->find(array('h1' => array('$in' => array('a', 'd'))));

As to why your query doesn’t work – you’re not using $or correctly (or infact, at all). This is the query you’ve put in the question reformatted:

$query = array(
   '$or' => array(
        array('h1' => 'a')
    ), 
    array('h1' => 'd')
);

Whereas you would need:

$query = array(
   '$or' => array(
        array('h1' => 'a'),
        array('h1' => 'd')
    )
);

If you have a look in the mongodb error log most likely it says something about that illegal loose top-level array in the conditions.