SQL Server - INNER JOIN WITH DISTINCT

Question

I am having a hard time doing the following:

select a.FirstName, a.LastName, v.District
from AddTbl a order by Firstname
inner join (select distinct LastName         


        

Answer 1

select distinct a.FirstName, a.LastName, v.District from AddTbl a inner join ValTbl v on a.LastName = v.LastName order by a.FirstName;

hope this helps