So I have 3 entities within one table. I need to be able to search 2 out of the 3 entities in one select statement, but I\'m not sure how to do this.
As commented by flu, if you want to retrieve some entities from different instances with a QueryBuilder instead of a DQL query, you can use an array as parameter:
$qb = $this->createQueryBuilder('u');
->where('u.id > 10') //an arbitrary condition, to show it can be combined with multiple instances tests
->andWhere('u INSTANCE OF :classes')
->setParameter('classes', ['Entity\Manager', 'Entity\Customer'])
;