When Querying the data with where Operators the result is not comming .

Hi,

I have tried lot to search for this but didn't get any solution yet which works.

I am using PHP curl to query the results .

when I do where like below it works fine. $where = array('role' => 'role name');

but when I do query it with below it just returns the error msg.

$where = array('role' => array('$nin' => 'role name'));
    [meta] => Array
        (
            [status] => fail
            [code] => 500
            [message] => Error: Internal Server Error
            [method_name] => queryUsers
        )

let me know how to resolve it.