I'm trying to put together an APEX class that will the User table and return the ID, based on a custom variable called Sales__c, for that user.  The ID will then be used to change the OwnerID field on the Account record.

Regardless of what I can think to try, I keep running in to walls.  Would greatly appreciate a gentle prodding in the correct direction.

Account[] Users = [Select a.Owner.Id, a.Owner.Sales__c from Account a  WHERE a.Owner.Sales__c  = '6579'];
           
a.OwnerID= Users.Id;

I've been working with several integration models, and have been quite successful in doing almost everything we need through SSIS.  HOWEVER, I've come to a huge brain-free area that I can't seem to think past.  I'm sure it's an easy fix, but I just can't resolve it...

If I do a join SOQL query, pulling back information from two or more tables, how do I pass that information on?

Example from some SFDC documentation:

SELECT Name, (SELECT LastName FROM Contacts) FROM Account

 If I run that query, I'll get back one sObject of type Account.  I can't assign anything to an sObject of type Contacts, because that's not what's coming back.

I'd really, really like to be able to write my queries in this fashion, but just can't figure out how to pass the data along.  Once I get the results back, how can I assign it to an sObject for actual use?

Someone, please... Help me get past this blindspot! 

Thanks.