@jkeppens Select/Where

<?php
include '/Users/ralphschindler/Projects/zf2/vendor/autoload.php';

use Zend\Db\Sql\Select;
use Zend\Db\Sql\Predicate;

$select = new Select;
$select->from('foo');

$select->where(['x' => null]);
$select->where(['x' => 5], 'OR');
// OR
$select->where(function ($where) {
    $where->isNull('x')->OR->equalTo('x', 5);
});
$select->where(new Predicate\Expression('x IS NULL or x = ?', 5));

echo @$select->getSqlString();