Skip site navigation (1) Skip section navigation (2)

Re: [HACKERS] JOIN syntax. Examples?

From: "Thomas G(dot) Lockhart" <lockhart(at)alumni(dot)caltech(dot)edu>
To: Hannu Krosing <hannu(at)trust(dot)ee>
Cc: "PGSQL HACKERS (E-mail)" <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: [HACKERS] JOIN syntax. Examples?
Date: 1998-12-15 01:01:01
Message-ID: 3675B4CD.99DC208D@alumni.caltech.edu (view raw or flat)
Thread:
Lists: pgsql-hackers
> > This one conflicts with Postgres' operator extensibility features, 
> > since it would look just like a legal operator.
> so does =

But in fact its usage for joins matches the typical usage elsewhere.

> Has anybody tried out DB2 ?
> I have downloaded it (for linux) but have not yet tried it.

Just downloaded it this morning (and afternoon, it's a thin pipe at home
for 60MB of files :) Have you looked at what it takes to do an
installation yet?

> Not to mention that both =* and =(+) are more concise and easier to
> follow, at least for one with my headshape.
> The standard is probably the 'worst common denominator' or something
> like that :(

DeJuan points out a major strength of the SQL92 syntax, which allows
multiple outer joins in the same query. One of my books shows an
example:

  select * from
    q1 full outer join q2 on (q1.id = q2.id)
       full outer join q3 on (coalesce(q1.id,q2.id)=q3.id)
       full outer join q4 on (coalesce(q1.id,q2.id,q3.id)=q4.id)

I suppose one can do something similar using a *= operator by using
parentheses? Not sure though...

                       - Tom

In response to

Responses

pgsql-hackers by date

Next:From: Tom LaneDate: 1998-12-15 01:18:10
Subject: Re: [HACKERS] Backend crash in opr_sanity regression test.
Previous:From: Hiroshi InoueDate: 1998-12-14 23:48:58
Subject: RE: [HACKERS] Projecting attributes of function return values

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group