Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: outer joins..

Re: outer joins..

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Sat, 15 Aug 1998 16:26:03 GMT
Message-ID: <01bdc869$239ac9f0$0300a8c0@WORKSTATION>

A possible answer -

	where
		a.col1 = b.col2(=)

forces a path from table A to table B.

Oracle may choose different paths for the two different scales of query when the queries are normal joins, but not be able to use the one it considers to be the better path when the outer join is used.

Run all 4 cases through explain plan, this may give you some clues.

sunita_at_postoffice.worldnet.att.net wrote in article <35D57C88.1081_at_postoffice.worldnet.att.net>...
> Can you please explain why it is behaving like this:
>
> WHen a query is expected to return fewer rows, outer joins
> bring back teh results quickly.
>
> WHen the query is expected to return large # of rows,
> regular joins bring back the results quickly..
>
> WHY????
>
Received on Sat Aug 15 1998 - 11:26:03 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US