Retrieve primary entities along with related entities with one QueryExpression

Retrieve related records for a parent record It’s possible to get related records of  a relationship when we retrieve a parent record using RelatedEntitiesQuery property in the RetrieveRequest. That means you have to construct the RetrieveRequest not using the Retrieve method from the OrganizationServiceProxy class. https://dyncrmexp.com/2017/10/24/retrieve-primary-entities-along-with-related-entities-with-one-queryexpression/comment-page-1/ by Khoa Nguyen