From: Josh Berkus <josh@agliodbs.com>
To: Richard Huxton <dev@archonet.com>
To: pgsql-sql@postgresql.org
Subject: Re: UPDATE ... FROM vs standard SQL
Date: Fri, 7 Jun 2002 11:50:55 -0700
Message-ID: <200206071150.55227.josh@agliodbs.com> (raw)
In-Reply-To: <200206071705.33642.dev@archonet.com>
References: <web-1502464@davinci.ethosmedia.com>
<200206071705.33642.dev@archonet.com>
Richard,
> Tell me about it. Where I'm using MySQL on client web-servers I find myself
> porting the data into PG to massage it then putting the results back into
> MySQL. One of the things missing from the various reviews/comparisons on the
> web is any actual comparison of usage for DBA tasks (as opposed to handling
a
> message-board app etc)
But MySQL does handle message-baord apps very well. If only MySQL AB and
NuSphere would stick to that and not try to poach in transactional database
space ...
> Nope - mostly work with PG/MySQL/MS-SQL/Access. I use all the features at
the
> psql prompt, but like to stick to the standard for app-generated queries.
Well, this will work on any database with *full* SQL92 support:
UPDATE tablea SET field3 = (SELECT field5
FROM tableb
WHERE tableb.field2 = tablea.field1);
... and won't be as slow as an IN query. Quite.
However, MS SQL 7.0 does not support correlated subqueries outside of the
WHERE clause (I'm not sure about SQL 2000). For MS Access, well, forget
using subqueries at all unless you have all day ...
And for MySQL, you're hosed. Tell your clients they need a different
database.
--
-Josh Berkus
______AGLIO DATABASE SOLUTIONS___________________________
Josh Berkus
Complete information technology josh@agliodbs.com
and data management solutions (415) 565-7293
for law firms, small businesses fax 621-2533
and non-profit organizations. San Francisco
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: josh@agliodbs.com, dev@archonet.com
Subject: Re: UPDATE ... FROM vs standard SQL
In-Reply-To: <200206071150.55227.josh@agliodbs.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox