Groups > comp.lang.java.databases > #330

Re: Joining(?) question

From	"Lee Fesperman" <lee.fesperman@THRWHITE.remove-dii-this>
Subject	Re: Joining(?) question
Message-ID	<72ed2328-62ae-491f-be9f-b6faad045e13@q26g2000prq.googlegroups.com> (permalink)
Newsgroups	comp.lang.java.databases
References	<geiv3f$c9g$1@aioe.org>
Date	2011-04-27 15:23 +0000
Organization	TDS.net

Show all headers | View raw

  To: comp.lang.java.databases
On Nov 1, 5:17 pm, Lew <no...@lewscanon.com> wrote:
> Lee Fesperman wrote:
> > On Oct 30, 5:27 am, Lew <no...@lewscanon.com> wrote:
> >> mdR wrote:
> >>> SELECT BM.PARENT, BM.ITEM, IM.DESC
> >>> FROM BM
> >>> JOIN IM ON IM.ITEM = BM.ITEM
> >>> WHERE BM.PARENT = 1;
> >> Different RDBMSes vary wrt JOIN syntax.  But RGB's version should have worked,
> >> too.
>
> >> Some allow
>
> >> SELECT BM.PARENT, BM.ITEM, IM.DESC
> >>   FROM BM JOIN IM
> >>   WHERE BM.PARENT = 1;
>
> >> if there's a FK on the ITEM column to the other table.
>
> > I realize that DBMS support of Standard SQL is weak, but which ones
> > support those semantics? According to SQL92, an unqualified JOIN
> > (without NATURAL, ON or USING) is the same as CROSS JOIN (that is, a
> > Cartesian Product.)
>
> Oops, left out the word "NATURAL", as in "NATURAL JOIN".

That certainly makes a difference and will give the right results
(given the table structure shown by the OP.) NATURAL joins on common
column names between the two tables.

FK joining is non-standard and begs the question: Which FK for which
table is used?

--
Lee Fesperman, FFE Software, Inc. (http://www.firstsql.com)
==============================================================
* The Ultimate DBMS is here!
* FirstSQL/J Object/Relational DBMS  (http://www.firstsql.com)

---
 * Synchronet * The Whitehouse BBS --- whitehouse.hulds.com --- check it out free usenet!
--- Synchronet 3.15a-Win32 NewsLink 1.92
Time Warp of the Future BBS - telnet://time.synchro.net:24

Back to comp.lang.java.databases | Previous | Next — Previous in thread | Find similar

Thread

Re: Joining(?) question "mdR" <mdr@THRWHITE.remove-dii-this> - 2011-04-27 15:23 +0000
  Re: Joining(?) question "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:23 +0000
    Re: Joining(?) question "Lee Fesperman" <lee.fesperman@THRWHITE.remove-dii-this> - 2011-04-27 15:23 +0000
      Re: Joining(?) question "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:23 +0000
        Re: Joining(?) question "Lee Fesperman" <lee.fesperman@THRWHITE.remove-dii-this> - 2011-04-27 15:23 +0000

csiph-web