Using Exists in Simple Update?
From: Lee E Parsons <lparsons_at_world.std.com>
Date: 1995/07/12
Message-ID: <DBKu41.HB4_at_world.std.com>#1/1
Date: 1995/07/12
Message-ID: <DBKu41.HB4_at_world.std.com>#1/1
I have been working on a test case involving the following table structures and data.
Table A (Key CHAR, data number) A NULL B NULL C NULL Table B (Key CHAR, data number) A 1 B 2 C 3 A 1 B 2 C 3
I can of course do
update a set a.DATA = (select max(DATA) from b where A.KEY = B.KEY)
But the use of the max looks a bit off. Is there a way to form this update
so that only the first occurence of KEY need be read from file B? I have
played with the WHERE EXISTS clause but can't seem to get it worked out.
--
Regards,
Lee E. Parsons
Systems Oracle DBA lparsons_at_world.std.com
Received on Wed Jul 12 1995 - 00:00:00 CEST