I've got a function written that runs a query based on parameters passed to the function.

I can't seem to figure out why doing the following returns a result:

function test($function_returned_array)
{
    $variable = 'Hello World';
    $sql = 'SELECT `name`, `pid`
            FROM `products`
            WHERE `name` IN (?)';
    $found = $this->db->get_array($sql, $variable);
}

While this doesn't return any results:

function test2($function_returned_array)
{
    $sql = 'SELECT `name`, `pid`
            FROM `products`
            WHERE `name` IN (?)';
    $found = $this->db->get_array($sql, $function_returned_array[0]);
}

$function_returned_array[0] is also equal to 'Hello World'. Shouldn't they both return the same results?

When I echo the values of $variable and $function_returned_array[0], they are both 'Hello World'

Here's the relevant parts of my PDO wrapper:

public function query(&$query, $params)
{
    $sth = $this->_db->prepare($query);

    if(is_null($params))
    {
        $sth->execute();
    }
    else if(is_array($params))
    {
        $sth->execute($params);
    }
    else
    {
        $sth->execute(array($params));
    }

    $this->_rows = $sth->rowCount();
    $this->_counter++;
    return $sth;
}

public function get_array(&$query, $params, $style = PDO::FETCH_ASSOC)
{
    $q = $this->query($query, $params);
    return $q->fetchAll($style);
}

I'm using PHP 5.3.5.

Any help would be appreciated.