On "left join"clause

Posted in 2008

Topics: Performance & Tuning, SQL Development & Query Writing

=?iso-8859-1?Q?Omar_Mu=F1oz?= — Fri, 24 Oct 2008 07:47:06 -0700 (PDT) — source: Usenet: comp.databases.informix

Hi. I'm taking a look at a sp code which uses "left join" syntax instead of the conventional "outer". That code has performance problems, but I found with "ser explain" that some fragmented tables were not excluding fragmnents, this issue was solved only by replacing "left join" with "outer". Some workmates told me that there wasn't any difference between both ways, so I would like to know if there is some tech note of warning about using "left join", or my workmates are right. Thanks in advance Omar Muñoz

↪ replying to =?iso-8859-1?Q?Omar_Mu=F1oz?=

Fernando Nunes — Sun, 26 Oct 2008 23:18:55 +0000 — source: Usenet: comp.databases.informix

Omar Mu'oz wrote: > Hi. > > I'm taking a look at a sp code which uses "left join" syntax instead of the conventional "outer". That code has performance problems, but I found with "ser explain" that some fragmented tables were not excluding fragmnents, this issue was solved only by replacing "left join" with "outer". Some workmates told me that there wasn't any difference between both ways, so I would like to know if there is some tech note of warning about using "left join", or my workmates are right. > > Thanks in advance > > Omar Mu'oz > > > It shouldn't make a difference. But it can make for the optimizer. Usually that means a Bug... The older your version is the easier it gets to hit one of them... Regards. -- Fernando Nunes Portugal http://informix-technology.blogspot.com My email works... but I don't check it frequently...