Avoid duplicate entry while using insert into .... select statement

 Avoid duplicate entry while using insert into .... select  statement

       Insert into Names

       select name.Value as name, abr.Value as abr 

       from  name

       INNER JOIN   abr ON name.RowID = abr.RowID

       where NOT EXISTS (select 1

                 from Names a

                 where a.name =name.Value

                 and a.abr = abr.Value)