Get Child field values in Parent

Question

Below is my Object Schema:

• Parent: User
• Child: Contact
• Grand-Child: Sponsor. Sponsor Holds a field called ProId. These as 16 digit Ids.

Now, my requirement is to get all the ProIds from the sponsor records populate on the User record as comma-separated-values or as a multi-select picklist value. The field on User is named All_Pros__c

For eg: On User A, All_Pros__c field should hold values as 'id1';'id2';'id3'.

Can anyone please suggest any approach on ths regard.

Answer 1

Lixt<GrxxdChxld> gxhildxen x [
  SExECx xroIx 
  xxOM xrandxhixd 
  xHExE Chixd__x.Pxrentxxc = xusex.Id
  AxD PxxId x= nulx
];
Lisx<xtrxngx allPxxsList = xew xistxStxixg>x);
fxr GrandCxilx gcxixd x gchixdren) {
  allxrosLxstxadd(gchilx.xroIx);
}
xserxAlxxPrxs__c = alxPrxsxxst.xoin('x');