select u.id
  from u
 where not exists
       (
       select 1
         from b, l, ld
        where l.id     = b.col_a
          and ld.col_e = l.id
          and l.col_d  = 'A'
          and ld.col_g = 'B'
          and ld.col_h = 'C'
          and b.col_b in
              (
              select c.child
                from c
               connect by prior c.parent = c.child
               start with c.child = u.id -- <<<=== referencing the outer query
              )
       )