exists clause

From: Marcin Buchwald <velvet_at_agora.pl>
Date: Wed, 7 Apr 2004 10:28:12 +0200
Message-ID: <c50e39$l4l$1@pippin.warman.nask.pl>

Are the two conditions equivalent?

---

and not exists (
  select 1 from plan_grzbietu p2, drzewo_mutacji d2   where p2.mutgrb=d2.mutacja
    and p.dow=p2.dow and p.drw1_xx=p2.drw1_xx and d.poziom<d2.poziom     and p.mutgrb in (

      select mutacja from drzewo_mutacji d3
       start with mutacja=d2.mutacja connect by prior root_xx=xx

)

)

---

and (
  select max(p2.mutgrb) from plan_grzbietu p2, drzewo_mutacji d2   where p2.mutgrb=d2.mutacja
    and p.dow=p2.dow and p.drw1_xx=p2.drw1_xx and d.poziom<d2.poziom     and p.mutgrb in (

      select mutacja from drzewo_mutacji d3
       start with mutacja=d2.mutacja connect by prior root_xx=xx

)

) is null

---

on ORA9203EENT they are not in my specific query.

Could someone explain it to me?

Regards,

        Marcin Received on Wed Apr 07 2004 - 03:28:12 CDT