````php
$and = $qb->where()->andX();
$and->eq()->field(..)->literal(..);
$qb->getQuery();  // valid already

$and->eq()->field(..)->literal(..);
$and->eq()->field(..)->literal(..);
$and->eq()->field(..)->literal(..);
$and->eq()->field(..)->literal(..);
$qb->getQuery(); // WHERE .. AND (.. AND (.. AND(..))) or similar.
````