declare @graph table (parent bigint not NULL, child bigint not NULL, [weight] int not NULL, gID bigint, primary key(parent, child, [weight]), unique(child, parent, [weight]) );

insert into @graph(parent, child, [weight])
Values 
-- 1 граф
(1, 1, 1), (1, 2, 1), (1, 3, 10), (2, 3, 2), (3, 1, 3), (3, 6, 1), (6, 6, 2)
-- 2 граф
, (4, 4, 1), (4, 5, 1), (5, 4, 2), (5, 4, 1);

with t as ( select *, n = row_number() over( order by 1/0 ) from @graph )
  update t set gID = n from t;

declare @rc int = 1;

while @rc > 0 begin

  with t as ( select * from @graph )
     update t set gID = t1.gID
	   from t inner join t as t1 on t.child = t1.parent
	   where t.gID > t1.gID 
  ;
  set @rc = @@ROWCOUNT;

  with t as ( select * from @graph )
     update t set gID = t1.gID
	   from t inner join t as t1 on t1.child = t.parent
	   where t.gID > t1.gID 
  ;
  set @rc = @rc + @@ROWCOUNT;

  with t as ( select * from @graph )
     update t set gID = t1.gID
	   from t inner join t as t1 on t1.child = t.child
	   where t.gID > t1.gID 
  ;
  set @rc = @rc + @@ROWCOUNT;

  with t as ( select * from @graph )
     update t set gID = t1.gID
	   from t inner join t as t1 on t1.parent = t.parent
	   where t.gID > t1.gID 
  ;
  set @rc = @rc + @@ROWCOUNT;

end;

select * from @graph order by gID;

select gID, max([weight]) from @graph group by gID

with t as ( select * from @graph )

     update t set gID = t1.gID
	   from @graph t inner join @graph as t1 on t1.parent = t.parent
	   where t.gID > t1.gID