Re: Select from (select)

Posted in 2004

Abdullah Kauchali — Sun, 9 May 2004 12:00:03 +0200 — source: Usenet: comp.databases.informix

> select x from table(multiset(select x from my_table)) as mt> > Are there any caveats (performance wise) of using "table(multiset())"? Kind regards Abdullah

↪ replying to Abdullah Kauchali

KA — Sun, 9 May 2004 16:12:18 -0400 — source: Usenet: comp.databases.informix

Yes. If you can do something without using it, don't use it. But in some cases (aggregations from multiple tables returned in one result set etc) or complex queries it can be very useful. The informix optimizer seems to be very primitive so for complex queries this one can be used to force it to run one part of the query first and then join to the next part. "Abdullah Kauchali" <abdullah.kauchali@someplace.com> wrote in message news:c7kvfh$khc$1@ctb-nnrp2.saix.net... > > > select x from table(multiset(select x from my_table)) as mt> > > > > > > Are there any caveats (performance wise) of using "table(multiset())"? > > Kind regards > > Abdullah > >