× The internal search function is temporarily non-functional. The current search engine is no longer viable and we are researching alternatives.
As a stop gap measure, we are using Google's custom search engine service.
If you know of an easy to use, open source, search engine ... please contact support@midrange.com.



As I said,  I would be corrected shortly.    Here's the definitive answer
I just got.

----------------------------------------------------
The SQL INNER JOIN clause use to "force" the join order, but that behavior
changed in V4R5 - now the optimizer always tries to see if there's a better
join order.  There is a QAQQINI option that can be used to re-enable the
old INNER JOIN behavior.

Kent Milligan, DB2 UDB for iSeries Technology Team
--------------------------------------------------------------------------------------------------

I copied Kent on my post.

John Carr



I think what Kent might have meant is dependant on how you do the join.
If you use a WHERE clause join,  The system will decide which is first.
But if you use the  JOIN clause I don't think it second guess's  you. (I
think all Query/400 joins are WHERE clause joins off the top of my head).

I may be wrong on that if it has changed in a very recent release.    I
probably will be corrected shortly if I am incorrect.

John
------------------------------------------------
Dale-

I was always under the impression that you should specify the file with the
least number of records FIRST in the join specifications.

However, I recently saw a post by Kent Milligan (DB2/400 guru at IBM) on
comp.sys.ibm.as400.misc that indicates the query optimizer will take care
of
this for you, so it doesn't matter which file you specify first.




As an Amazon Associate we earn from qualifying purchases.

This thread ...


Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.