How to get related records of child from parent object that has hierarchial relationship?

Question

i have a use case where we have Account record and every account has a hierarchial relationship with account itself. i need to display the related list of child accounts contacts on the master account. how can we accomplish this?

what is the relationship name to query an account itself when in hierarchy relationship?

Example: Account A- Parent , Account B-Child to A, Account C- Child to A,

How can i display (using VF) on the account A the contact records of Account B and C? Any help is highly appreciated.

Answer 1

Once you have the Parent Account ID it is simple:

Here Account__c is the API name of the lookup to the parent account (change as needed) and parentAccount is the apex ID property having the ID of the parent account

Account[] childAccounts = [Select ID, (Select ID, LastName From Contacts) from Account where Account__c = :parentAccount];