Re: Complex outer joins? - Mailing list pgsql-sql

From Tom Lane
Subject Re: Complex outer joins?
Date
Msg-id 9388.1048745899@sss.pgh.pa.us
Whole thread Raw
In response to Re: Complex outer joins?  (Greg Stark <gsstark@mit.edu>)
List pgsql-sql
Greg Stark <gsstark@mit.edu> writes:
> Yeah, that's not a particularly enlightening case because if you convert the
> right joins to left joins you see that these aren't actually similar queries
> at all.

> the first is 
>  "C left join (G left join L)" 
> and the second is
>  "G left join (C left join L)"

> They only look similar superficially when written using right joins but
> they're actually totally different structures.

Yup, you're quite right.  What's bothering me is that AFAICS they are
extremely similar in the Oracle notation too: put the (*) on the other
side of one of the equality clauses, and you convert one case to the
other.  So how can you assert that Oracle's notation is not sensitive
to join order?
        regards, tom lane



pgsql-sql by date:

Previous
From: Stephan Szabo
Date:
Subject: Re: Complex outer joins?
Next
From: Josh Berkus
Date:
Subject: Re: Database not restarting