id k1 k2 d1 d2 d3
 0    1     1   x   x   x 

id k1 k2 d1 d2 d3 d4
 0    1     1   x   x   x  x
 0    1     2   x   x   x  x

id k1 k2 d1 d2 d3
 1    1     1   x   x   x 

id k1 k2 d1 d2 d3 d4
 1    1     1   x   x   x  x
 2    1     2   x   x   x  x

  update Таблица  1  t0
  set id=
   (
    select
           id
    from
     (
      select
                   k1,
                   k2,
                   rdrownum() as id -- UDF - counter сампловская
      from      
      (
          select 
                   coalesce(t1.k1,t2.k1),
                   coalesce(t1.k2,t2.k2),

            from Таблица  1  t1
            full outer join Таблица  2  t2 on
                                                  t1.k1  =  t2.k1  and
                                                  t1.k2 =  t2.k2
      ) t3
      group by
                     k1,
                     k2
     ) t4
    where
          t4.k1  =  t0.k1  and
          t4.k1 =  t0.k1
   );